JP3819675B2 - How to write servo pattern - Google Patents

Description

ヘッド幅は、データ記録表面の半径方向に沿った寸法を表す。
【００３２】
従来のシリンダ型のハード・ディスク駆動装置においては、全てのデータ記録表面のデータ記録トラックの数は同じであった。これと対照的に、本発明においては、一つのデータ記録面例えば記録面＃１のデータ記録トラックの数は他のデータ記録面例えば記録面＃２のデータ記録トラックの数と異なり、そして一つのデータ記録面のデータ記録トラック相互間のギャップ幅は他のデータ記録面のデータ記録トラック相互間のギャップ幅と異なる。
【００３３】
一つのデータ記録面の全てのデータ記録トラックは同じトラック幅を有し、そして全てのギャップは同じギャップ幅を有する。
【００３４】
他のデータ記録面の全てのデータ記録トラックは同じトラック幅を有し、そして全てのギャップは同じギャップ幅を有する。
【００３５】
図１０及び図１１は、本発明に従う動作のフロー・チャートを示し、そして図５乃至図９は、１つのデータ記録面にこれの読み取り／書き込みヘッドを使用してサーボ・パターンＡ及びＢを書き込む動作を示す。
【００３６】
動作は図１０のブロック３１で開始する。動作はブロック３２に進み、そしてここでＭＰＵ１６は第１データ記録面＃１を選択する。第１記録面＃１にサーボ・パターンを書き込む動作の間、ヘッド＃１だけが動作され、そして他のヘッド＃２乃至＃６は動作されない。
【００３７】
動作はブロック３３に進み、そしてここでＭＰＵ１６及びＶＣＭ／スピンドル・ドライバ１４は、支持アーム４が内側クラッシュ・ストップ１８により停止されるまでＶＣＭ１１に駆動電流を印加して支持アーム４を移動させ、この結果ヘッド＃１は基準位置Ｐ１即ち最も内側のデータ記録トラックに位置決めされる。
【００３８】
動作はブロック３４に進み、そしてここでサーボ・トラック番号が１にセットされる。動作はブロック３５に進み、そしてここでサーボ・パターンがサーボ・トラック番号Ｎに書き込まれる。ブロック３５の動作において、ヘッド＃１は図５に示されているように位置Ｐ１に位置決めされる。即ち、サーボ・パターンＡ及びＢがデータ記録面＃１に書き込まれ、そしてこの場合には記録面＃１のヘッド＃１は１．０μｍのヘッド幅Ｈ_Ｗを有する。
【００３９】
図５において、位置Ｐ１Ｃは位置Ｐ１に位置決めされているヘッド＃１の中心を示す。サーボ・パターンＡ１及びＢ１がサーボ・トラック＃１に記録される。サーボ・パターンＡ１及びＢ１を書き込むために、図３の読み取り／書き込み回路１２は、パターンＡを書き込むための交流信号及びパターンＢを書き込むためのＤＣ信号をヘッド＃１に印加する。図を簡略化するために、２つのサーボ・パターンだけが示されている。
【００４０】
動作はブロック３５Ａに進み、そしてここでヘッド＃１は位置Ｐ１に停止され、そしてサーボ・パターンＡ１及びＢ１を読みとり、そしてヘッド＃１の出力信号の振幅がＭＰＵ１６により検出されてメモり１７に記憶される。
【００４１】
動作はブロック３６に進み、そしてここでヘッド＃１は位置Ｐ１から最も外側の位置に向かって移動され、そしてブロック３５で書き終えたサーボ・パターンＡ１及びＢ１をヘッド＃１が移動しながら読み取り、これの出力信号の振幅がＭＰＵ１６により測定される。
【００４２】
動作はブロック３７に進み、そしてここでＭＰＵ１６は出力信号の振幅が、ブロック３５Ａで測定した振幅の（５０−Ｇ_Ｗ／２％）にまで減少されたか否かを調べる。値１００％は、ブロック３５Ａでヘッド＃１がサーボ・パターンＡ１及びＢ１に完全に重なっているときの出力信号のフル振幅を示す。Ｇ_Ｗはデータ記録トラック相互間のギャップ幅である。
【００４３】
この実施例では、ギャップ幅Ｇ_Ｗはヘッド幅Ｈ_Ｗの１０％に選択されており、従って出力信号の振幅が値（５０−Ｇ_Ｗ／２％）、即ち（５０−５％）＝４５％まで減少したことは、図１２に示すように、１．０μｍのヘッド＃１が位置Ｐ１から距離（Ｈ_Ｗ＋Ｇ_Ｗ）／２＝０．０５μｍだけ移動されたことを示す。
【００４４】
もしもブロック３７の答えがノーであるならば、動作はブロック３８に進み、そしてここでヘッドが外側のクラッシュ・ストップ１９に到達したか否かを調べる。もしもブロック３８の答えがイエスであるならば、動作は図１１のブロック４３に進む。もしもブロック３８の答えがノーであるならば、動作はブロック３６に戻る。もしもブロック３７の答えがイエスであるならば、このことは、ヘッド＃１が図６の位置Ｐ２にまで移動されていることを示す。動作は図１１のブロック３９に進み、そしてここでヘッド＃１の移動が位置Ｐ２で停止される。
【００４５】
動作はブロック４０に進み、そしてここでサーボ・トラック番号がＮ＋１に歩進される。動作はブロック４１に進み、そしてここで、図６に示すように位置Ｐ２に停止されているヘッド＃１がサーボ・パターンＡ１及びＢ１の上にサーボ・パターンＡ２及びＢ２をそれぞれ重ねて書き込む。サーボ・パターンＡ１及びＢ１の上端と位置Ｐ１Ｃとの間の距離は、Ｈ_Ｗ／２即ち０．５μｍであり、そして位置Ｐ１Ｃとサーボ・パターンＡ２及びＢ２との間の距離はＧ_Ｗ／２であり、そしてこれはヘッド幅Ｈ_Ｗの５％即ち０．０５μｍである。
【００４６】
動作はブロック４２に進み、そしてここでＭＰＵ１６は数Ｎ＋１が予定の最大サーボ・トラック数（例えば１００００サーボ・トラック）に等しいか又はこれよりも大きいか否かを調べる。もしもブロック４２の答えがノーであるならば、動作はブロック３５Ａに戻り、そしてブロック３５Ａ乃至４２の動作が繰り返される。
【００４７】
図７乃至図９はこの繰り返し動作において書き込まれるサーボ・パターンを示す。図７において、ヘッド＃１は位置Ｐ２から位置Ｐ３まで距離Ｄ＝（Ｈ_Ｗ＋Ｇ_Ｗ）／２だけ移動される。位置Ｐ３において、ヘッド＃１はサーボ・パターンＡ２及びＢ２の上にサーボ・パターンＢ３およびＡ３をそれぞれ重ねて書き込む。サーボ・パターンＡ２の下側の部分はサーボ・パターンＢ３に代えられ、そしてサーボ・パターンＢ２の下側の部分はサーボ・パターンＡ３に代えられていることが明らかである。図８において、ヘッド＃１は位置Ｐ３から位置Ｐ４まで距離Ｄ＝（Ｈ_Ｗ＋Ｇ_Ｗ）／２だけ移動される。位置Ｐ４において、ヘッド＃１はサーボ・パターンＢ３及びＡ３の上にサーボ・パターンＢ４およびＡ４をそれぞれ重ねて書き込む。図９において、ヘッド＃１は位置Ｐ４から位置Ｐ５まで距離Ｄ＝（Ｈ_Ｗ＋Ｇ_Ｗ）／２だけ移動される。位置Ｐ５において、ヘッド＃１はサーボ・パターンＢ４及びＡ４の上にサーボ・パターンＡ５およびＢ５をそれぞれ重ねて書き込む。サーボ・パターンＢ４の下側の部分はサーボ・パターンＡ５に代えられ、そしてサーボ・パターンＡ４の下側の部分はサーボ・パターンＢ５に代えられていることが明らかである。
【００４８】
このようにして、ヘッド＃１は距離Ｄ＝（Ｈ_Ｗ＋Ｇ_Ｗ）／２だけデータ記録面の最も外側の位置に向かって移動され、そして各位置に置いてヘッド＃１は新たなサーボ・パターンを書き込む。ブロック４２の答えであるイエスにより示されるようにヘッド＃１が十分な数のサーボ・トラックを書き込んだときに、第１データ記録面＃１にサーボ・パターンＡ及びＢを書き込む動作は終了される。ハード・ディスク制御回路１５又はＭＰＵ１６内のカウンタが半径方向におけるヘッド＃１の距離Ｄ＝（Ｈ_Ｗ＋Ｇ_Ｗ）／２の移動の回数をカウントし、そしてこの値はメモリ１７に記憶され、これによりＭＰＵ１６はこのカウント数を参照することにより記録面に書き込まれたサーボ・トラック数を知ることができる。
【００４９】
図９を再び参照すると、読み取り／書き込み動作の間、ヘッド＃１はサーボ・パターンＡ及びＢを感知して、図３の読み取り／書き込み回路１２を介してハード・ディスク制御回路１５に帰還信号を供給する。ハード・ディスク制御回路１５はこの帰還信号に応答してＶＣＭ／スピンドル・ドライバ１４を制御し、この結果ＶＣＭ１１は、ヘッド＃１の中心がパターンＡ２及びＢ２とパターンＢ３及びＡ３との境界に整列するように支持アーム４を移動させる。この境界はトラック中心ＴＣと呼ばれ、この場合にはＴＣ１であり、そしてデータ記録ディスクが読みとり／書き込み動作で回転されると、データ記録トラック＃１が規定される。データ記録トラックの幅はヘッド＃１の幅（この場合には１．０μｍ）に等しい。 データ記録トラック＃１の中心ＴＣ１とデータ記録トラック＃２の中心ＴＣ２とについて説明すると、中心ＴＣ１及びＴＣ２との距離は２Ｄ＝Ｈ_Ｗ＋Ｇ_Ｗに等しく、言い換えると、ヘッド幅Ｈ_Ｗの１０％のギャップＧ_Ｗがデータ記録トラック＃１と＃２との間に存在する。
【００５０】
動作はブロック４３に進み、そしてここでＭＰＵ１６はサーボ・パターンが全ての記録面に書き込まれたか否かを調べる。もしもブロック４３の答えがノーであるならば、動作はブロック４４に進み、そしてここでＭＰＵ１６は次のヘッド＃２を選択する。動作はブロック３３に戻り、そしてブロック３３乃至４３の動作が繰り返されて、上述のようにして残りのデータ記録面＃２乃至＃６にサーボ・パターンＡ及びＢが書き込まれる。この繰り返し動作においてヘッド幅０．６μｍの第２ヘッド＃２を使用して第２データ記録面＃２にサーボ・パターンが書き込まれる。第２データ記録面＃２にサーボ・パターンを書き込む動作の間は、ヘッド＃２だけが使用され、残りのヘッド＃１及び＃３乃至＃６は使用されない。ヘッド＃２のヘッド幅Ｈ_Ｗ即ちデータ記録トラックの幅は０．６μｍであり、そしてギャップ幅Ｇ_Ｗは１０％即ち０．０６μｍである。ヘッド幅１．４μｍの第３ヘッド＃３を使用して第３記録面＃３にサーボ・パターンを書き込む間、ヘッド＃３だけが動作され、そして残りのヘッド＃１、＃２及び＃４ー＃６は動作されない。データ記録トラックの幅は１．４μｍであり、そしてギャップ幅は１０％即ち０．１４μｍである。全てのデータ記録面＃１乃至＃６にサーボ・パターンが書き込まれたことはブロック４３に答えイエスにより示される。データ記録面＃１乃至＃６は次の表２に示すようなデータ・トラック幅及びギャップ幅を有する。そして、データ記録面＃１（＃４）、＃２（＃５）及び＃３（＃６）の隣接するデータ記録トラックのトラック・ピッチは互いに異なる。
【００５１】
【表２】

ヘッド幅が広くなるにつれて、記録面のトラックの数が減少しそしてギャップの幅が増大する。記録面＃３及び＃６は残りの記録面よりも少ないトラック数そして広いギャップを有する。このことは記録面＃３及び＃６のデータ容量が残りの記録面よりも少ないことを意味する。前述のように、ＭＰＵ１６は記録面＃１乃至＃６のサーボ・トラック数を記憶している。次のステップにおいて、動作はブロック４５に進み、そしてここでＭＰＵ１６は、データ記録面＃１乃至＃６のサーボ・トラック数（Ｎ_２）即ちカウント値に基づいて全ての記録面＃１乃至＃６のデータ記録トラックの総数（Ｎ_１）を調べる。このために次式を使用する。
【００５２】
Ｎ_１＝Ｎ_２／２−１
動作はブロック４６に進み、そしてここでＭＰＵ１６は総数Ｎ_１が予定数”Ｘ”に等しいか又は大きいか否かを調べる。もしもブロック４６の答えがイエスであるならば、動作はブロック４８に進み、そしてここで動作は終了する。もしもブロック４６の答えがノーであるならば、動作はブロック４７に進み、そしてここでＭＰＵ１６は、図１３及び図１４に示すように隣接するデータ記録トラックが互いに重なるようにサーボ・パターンを再書き込みする動作を開始する。
【００５３】
図１３及び図１４を参照すると、動作はブロック５１で開始する。動作はブロック５２に進み、そしてここでＭＰＵ１６はＹ＝０を指定する。次式が示すように、Ｙは隣接するデータ記録トラックの重なり幅を指定する値を表す。
【００５４】
重なり幅＝ヘッド幅（Ｈ_Ｗ）× Ｙ（％）
Ｙ＝０は、図１５（Ａ）に示すように、隣接するデータ・トラック＃１及び＃２の重なり幅が零でありそしてデータ・トラック＃１及び＃２相互間のギャップが零（Ｇ_Ｗ＝０）であることを示す。言い換えると、図１５（Ａ）に示すように、データ記録トラック＃１及び＃２が重なることなく又ギャップを生じることなく隣接するようにサーボ・パターンが再書き込みされることを示す。
【００５５】
ブロック５２において値Ｙ＝０を最初に指定する理由は、最小数のサーボ・トラック従って最小数のデータ記録トラックを含む記録面のデータ記録トラックは最も広いトラック幅を有し、たとえデータ・トラック相互間のギャップが零に減少されたとしても、この最も広いデータ・トラックにおいてはエラーの発生確率及びＳ／Ｎ比が低下する確率が低いからである。
【００５６】
動作はブロック５３に進み、そしてここでＭＰＵ１６は最小数のサーボ・トラックを含むデータ記録面のヘッドを選択する。上述のように、ＭＰＵ１６はデータ記録面＃１乃至＃６に書き込まれたサーボ・トラックの数をカウンタに記録しており、そしてＭＰＵ１６は最小数のデータ記録トラックを含む記録面、例えば記録面＃３を選択することができる。動作はブロック５４に進み、そしてここで記録面＃３のヘッド＃３が基準位置に移動される。ブロック５８において、パラメータＹ＝０に基づいて位置Ｐ１からＰ２まで、Ｐ２からＰ３までのヘッド＃３の移動距離が距離Ｈ_Ｗ／２ に選択され、重なりのないデータ記録トラック＃１及び＃２を形成することを除き、図１０及び図１１のブロック３３乃至４２の動作と同じ動作がブロック５４乃至６３において行われることに注目されたい。
【００５７】
データ記録面＃３の全表面にサーボ・パターンが再書き込みされた後に、動作は図１４のブロック６４に進み、そしてここで図１１のブロック４５と同じようにして、ＭＰＵ１６は、データ記録面＃１乃至＃６のサーボ・トラック数（Ｎ_２）即ちカウント値に基づいて全ての記録面＃１乃至＃６のデータ記録トラックの総数（Ｎ_１）を調べる。上述のようにこの動作において次式を使用する。
【００５８】
Ｎ_１＝Ｎ_２／２−１
動作はブロック６５に進み、そしてここでＭＰＵ１６は総数Ｎ_１が予定数”Ｘ”に等しいか又は大きいか否かを調べる。もしもブロック６５の答えがイエスであるならば、動作はブロック７１に進み、そしてここで動作は終了する。もしもブロック６５の答えがノーであるならば、動作はブロック６６に進み、そしてここでＭＰＵ１６は、全ての記録面＃１乃至＃６が再書き込みされたか否かを調べる。もしもブロック６６の答えがノーであるならば、動作はブロック６７に進み、そしてここでＭＰＵ１６は次に少ないサーボ・トラック数を含む記録面を選択する。この場合には記録面＃６が選択される。その理由は、この記録面がヘッド幅１．４μｍのヘッド＃６により書き込まれ、そしてデータ・トラック数が残りの記録面よりも少ないからである。
【００５９】
サーボ・パターンＡ及びＢを再書き込みするために動作はブロック５４に戻り、そしてブロック５４乃至６５の動作が繰り返される。もしもブロック６５の答えがノーでありそしてブロック６６の答えがノーであるならば、サーボ・パターンが残りの記録面例えば＃１又は＃４に再書き込みされる。上述の動作を繰り返した後に、もしもブロック６５の答えがノーでありそしてブロック６６の答えがイエスであるならば、このことは、図１５（Ａ）に示すように互いに重ならないデータ記録トラックを形成するように全てのデータ記録面＃１乃至＃６にサーボ・パターンが再書き込みされたにもかかわらず、全てのデータ記録面のデータ記録トラックの総数が予定数”Ｘ”よりも少ないことを表す。
この場合には、動作はブロック６８に進み、そしてここでＭＰＵ１６は、重なり幅の値をＹから新たな値Ｙ＋１０に変更する。ブロック６８の動作を説明すると、このブロック６８は、ブロック６６の答えがイエスであるごとに、次の動作を行うように次の値の一つを選択する。
【００６０】
ケース１の動作： Ｙ＝０
ケース２の動作： Ｙ＝１０
ケース３の動作： Ｙ＝２０
即ち、ブロック６８はブロック６６の答えイエスに応答してＹの値を増大する。
【００６１】
ケース１の動作は図１５（Ａ）に示されており、そしてここでは、データ記録トラック＃１及び＃２が互いに重なることなくそしてギャップを有することなく形成即ち規定されるように、ヘッドが距離Ｄ_１＝Ｈ_Ｗ／２だけ移動されてサーボ・パターンＡ及びＢを再書き込みする。ケース２の動作は図１５（Ｂ）に示されており、そしてここで、Ｙ＝１０は、ヘッド幅の１０％だけ互いに重ねられたデータ記録トラック＃１及び＃２を形成即ち規定するようにサーボ・パターンが再書き込みされることを表す。ここで、重なり幅を表す次式を思い起こされたい。
【００６２】
重なり幅＝ヘッド幅（Ｈ_Ｗ）× Ｙ％
データ記録トラックが１０％だけ重なるようにするために、ヘッドはＤ_２＝Ｈ_Ｗ／２−（Ｈ_Ｗ×０．０５）の距離だけ移動される。即ち、ヘッドはヘッド幅の４５％に等しい距離だけ移動される。ケース３の動作は図１５（Ｃ）に示されており、ここではヘッド幅の２０％だけ互いに重なったデータ記録トラック＃１及び＃２を形成即ち規定する用にサーボ・パターンＡ及びＢが再書き込みされる。データ記録トラックを２０％だけ互いに重ねるために、ヘッドはＤ_３＝Ｈ_Ｗ／２−（Ｈ_Ｗ×０．１）の距離だけ移動される。即ち、ヘッドはヘッド幅の４０％に等しい距離だけ移動される。
【００６３】
このようにして、ＭＰＵ１６は、ブロック６５及び６６において全てのデータ記録面のデータ記録トラックの総数が、所定の数”Ｘ”に到達したか否かを調べ、もしも到達していないならば、ＭＰＵ１６は重なり幅を次の値に増大しそしてこの新たな値を用いてサーボ・パターンを再書き込みする。ブロック６９に示されているように、本発明の実施例ではＹ＝２０が重なりの最大値であり、従ってもしもブロック６９の答えがイエスである場合には、動作はブロック７０に進む。このことは、図１５（Ｃ）に示すようにそれぞれ２０％だけ重なるデータ記録トラックを形成するように距離Ｄ_３だけヘッドを移動させてサーボ・パターンを全ての記録面に再書き込みしたにも係わらず、全ての記録面＃１乃至＃６のデータ・トラックの総数が、予定数”Ｘ”に到達しなかったことを示す。ブロック７０は、結果が失敗（Ｆａｉｌ）であったことを示し、そして動作はこのブロック７０で終了する。
【００６４】
本発明の発明者による実験解析によると、ブロック７０に進む確率は１％よりも少なく、ケース１又はケース２の動作中に所望の数のデータ・トラックが書き込まれる確率が９９％よりも高いことが判った。
【００６５】
図１６（Ａ）は、本発明に従うデータ書き込み方式を示す。６つのデータ記録面＃１乃至＃６を与えるために３つの磁気記録ディスク５Ａ、５Ｂ及び５Ｃがスピンドル・モータ１３に装着されているものとする。
【００６６】
矢印２４Ａ乃至２４Ｆが示すように、第１データ記録面＃１の最も外側のデータ記録トラックに開始アドレスが割り当てられ、そしてこの第１記録面＃１のアドレスは最も外側のデータ記録トラックから最も内側のデータ記録トラックまで順番に割り当てられる。第１データ記録面＃１の最も内側のデータ記録トラックのアドレスの次のアドレスは、第２データ記録面＃２の最も外側のデータ記録トラックに割り当てられ、そしてこの第２データ記録面＃２のアドレスは、最も外側のデータ記録トラックから最も内側のデータ記録トラックまで順番に割り当てられ、そして以下同様に割り当てられる。
【００６７】
データは矢印２４Ａが示すように、第１記録面＃１の最も外側のデータ記録トラックから最も内側のデータ記録トラックに向かう方向に書き込まれ、次いで、データは矢印２４Ｂが示すように、第２記録面＃２の最も外側のデータ記録トラックから最も内側のデータ記録トラックに向かう方向に書き込まれ、次いで、 データは矢印２４Ｃが示すように、第３記録面＃３の最も外側のデータ記録トラックから最も内側のデータ記録トラックに向かう方向に書き込まれ、そして以下同様に書き込まれる。
【００６８】
図１６（Ｂ）は従来のシリンダ方式のデータ書き込み方式を示す。データは矢印２５Ａの方向に書き込まれ、次いで、データは矢印２５Ｂの方向に書き込まれ、次いで、データは矢印２５Ｃの方向に書き込まれ、そして以下同様にして書き込まれる。
【００６９】
表２に示すように、本発明においてはデータ記録面のそれぞれにおけるデータ記録トラックの幅及びギャップが異なることに基づいて、データ記録面＃１乃至＃６のそれぞれのデータ記録トラックの数が異なるので、図１６（Ａ）に示すデータ書き込み方式を使用する。
【００７０】
【発明の効果】
本発明は、ＧＭＲヘッドに対するデータ記録トラックが一様なトラック・ピッチで形成される場合に、ＧＭＲヘッドのデータ記録トラック相互間に無用で且つ無駄なスペースが形成されるという前述の第１の問題点を解決する。
【００７１】
更に、本発明は、以下に示すように前述の第２の問題点を解決する。
トラック・ピッチが固定されている従来の方式では、前述のように帰還信号の変動は次のようになる。
トラック幅（μｍ） ０．６ １．０ １．４
トラック・ピッチ（μｍ） １．６ １．６ １．６
トラック・ピッチの１０％（μｍ） ０．１６ ０．１６ ０．１６
帰還信号の変動 ２６．７％ １６．０％ １１．４％
トラック・ピッチがトラック幅に依存して変動する本発明の方式では、帰還信号の変動は下記のように一定になる。
トラック幅（μｍ） ０．６ １．０ １．４
トラック・ピッチ（μｍ） ０．６６ １．１ １．５４
トラック・ピッチの１０％（μｍ） ０．０６６ ０．１１ ０．１５４
帰還信号の変動 １１．０％ １１．０％ １１．０％
【図面の簡単な説明】
【図１】一様なトラック・ピッチを有する従来のデータ・トラックを使用してＧＭＲヘッドを配列することにより生じる問題点を示す図である。
【図２】従来のハード・ディスク・ドライブ装置において使用されるシリンダの概念を説明するための３つの磁気記録ディスクを示す図である。
【図３】ハード・ディスク・ドライブ装置に含まれる回路のブロックを示す図である。
【図４】データ記録ディスク及びサーボ・パターンにより規定されるデータ記録トラックを示す図である。
【図５】本発明のサーボ・パターンを書くステップを示す図である。
【図６】本発明のサーボ・パターンを書くステップを示す図である。
【図７】本発明のサーボ・パターンを書くステップを示す図である。
【図８】本発明のサーボ・パターンを書くステップを示す図である。
【図９】本発明のサーボ・パターンを書くステップを示す図である。
【図１０】サーボ・パターンを書くための、本発明に従うフローチャートを示す図である。
【図１１】サーボ・パターンを書くための、本発明に従うフローチャートを示す図である。
【図１２】本発明に従う１つの位置から次の位置へのヘッドの移動を示す図である。
【図１３】サーボ・パターンを再書き込みするための本発明に従うフローチャートを示す図である。
【図１４】サーボ・パターンを再書き込みするための本発明に従うフローチャートを示す図である。
【図１５】本発明に従うサーボ・パターンを再書き込みするための動作を示す図である。
【図１６】ハード・ディスク・ドライブ装置のアドレス方式及び従来のハード・ディスク・ドライブ装置のアドレス方式を示す図である。
【符号の説明】
１、２、３・・・ヘッド、
４・・・支持アーム、
５・・・ディスク、
７・・・ヘッド支持アーム、
１１・・・ＶＣＭ、
１２・・・読み取り／書き込み回路、
１３・・・スピンドル・モータ、
１４・・・ＶＣＭ／スピンドル・ドライバ、
１５・・・ハード・ディスク制御回路、
１６・・・ＭＰＵ、
１７・・・メモリ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for writing a servo pattern on a data recording surface of a rotating data recording disk.
[0002]
[Prior art]
Giant magnetoresistive (GMR) heads have been developed as next generation read / write heads for hard disk drive devices. A GMR head can generate an output signal that is larger than the output signal generated by a conventional magnetoresistive (MR) head. This ability to generate a large output signal makes it possible to reduce the head width of the GMR head.
[0003]
[Problems to be solved by the invention]
The GMR head is manufactured by an MR head manufacturing process, and therefore the head width of the GMR head is determined by an error in the manufacturing process of the MR head. The head width of the conventional MR head is 2 μm (1 μm = 10 ^-6 Meter), the head width of the GMR head is 1 μm, and the error of the manufacturing technology of the MR head is ± 0.4 μm. Since an error of ± 0.4 μm applies to both MR and GMR heads, the head width of the MR head is 2 μm ± 0.4 μm, that is, the head width of the MR head varies from 1.6 μm to 2.4 μm. And the head width variation or variation is 20%, and the head width of the GMR head is 1 μm ± 0.4 μm, ie the head width of the GMR head varies from 0.6 μm to 1.4 μm, and the head The variation or variation in width is 40%. Thus, it should be noted that the head width variation of the MR head is 20%, whereas the head width variation of the GMR head is 40%, which is larger than the MR head variation.
[0004]
A uniform track pitch has been used in the track arrangement of conventional MR heads. The track pitch is the distance between the track center of one track and the track center of the next track.
[0005]
If the uniform track pitch of the MR head is used in the GMR head, the following first problem occurs as shown in FIG. As described above, the head width of the GMR head varies from 0.6 μm to 1.4 μm. For ease of explanation, three types of GMR heads 1, 2 and 3 are shown in FIG. That is, the GMR head 1 has a head width of 1.4 μm, the GMR head 2 has a head width of 1.0 μm, and the GMR head 3 has a head width of 0.6 μm. The track widths of all the tracks 1, 2 and 3 are set to a width of 1.4 μm which is the maximum head width of the GMR head, and a uniform track pitch is used for all the tracks. An interval (gap) for separating two adjacent tracks is provided. The centers of the GMR heads 1, 2 and 3 are aligned with the track center of each track. It is clear that there is wasted space between GMR heads 1 and 2 and between GMR heads 2 and 3 that is not used.
[0006]
The following second problem occurs in relation to the servo pattern provided on the track. Servo patterns A and B are written to define the track and read by the head to generate a feedback signal that is supplied to the hard disk controller. The details of the servo patterns A and B are shown in FIGS. 4B and 4C. Servo pattern A has opposite magnetization directions arranged alternately, and servo pattern B has a uniform magnetization direction. The hard disk controller positions the center of the head at the track center in response to the feedback signal. Assume that GMR heads 1, 2 and 3 are shifted from the track center by 10% of the track pitch, as indicated by the dotted lines in FIG. For example, track pitch = track width × 1.1 = 1.4 μm × 1.1 = 1.6 μm, and shift distance = track pitch × 0.1 = 0.16 μm. In this case, the GMR heads 1, 2 and 3 are shifted with respect to the servo pattern B, and the fluctuation of the level of the feedback signal detected by the GMR heads 1, 2 and 3 is as follows.
[0007]
For GMR head 1 having a head width of 1.4 μm:
0.16 μm / 1.4 μm = 0.114
That is, the level of the feedback signal is reduced by 11.4%.
[0008]
For GMR head 2 having a head width of 1.0 μm:
0.16 μm / 1.0 μm = 0.16
That is, the level of the feedback signal is reduced by 16%.
[0009]
For the GMR head 3 having a head width of 0.6 μm:
0.16 μm / 0.6 μm = 0.267
That is, the level of the feedback signal is reduced by 26.7%.
[0010]
Calculates the variation in the level of the feedback signal detected by a conventional MR head having a head width of 2.4 μm, a conventional MR head having a head width of 2.0 μm, and a conventional MR head having a head width of 1.6 μm Then it is as follows. Track pitch = track width × 1.1 = 2.4 μm × 1.1 = 2.6 μm, and shift distance = track pitch × 0.1 = 0.26 μm.
[0011]
For MR heads with a head width of 2.4 μm:
0.26 μm / 2.4 μm = 0.108
That is, the level of the feedback signal is reduced by 10.8%.
[0012]
For an MR head with a head width of 2.0 μm:
0.26 μm / 2.0 μm = 0.13
That is, the level of the feedback signal is reduced by 13%.
[0013]
For an MR head with a head width of 1.6 μm:
0.26 μm / 1.6 μm = 0.163
That is, the level of the feedback signal is reduced by 16.3%.
[0014]
When the head is thus shifted by a distance of track pitch × A, the level of the feedback signal of the MR head to the hard disk controller fluctuates from 10.8% to 16.3%, The level of the feedback signal of the GMR head to the disk controller varies from 11.4% to 26.7%.
[0015]
When the fluctuation range becomes large, an undesirable phenomenon such as oscillation of the entire servo system may occur. Therefore, it is desirable that the fluctuation range of the feedback signal to the hard disk controller is small.
[0016]
[Means for Solving the Problems]
The method of the present invention writes a servo pattern defining a plurality of data recording tracks of a rotating data recording disk included in a disk drive device by a read / write head.
(A) positioning the write / read head at a position along the radial direction of the rotating data recording disk;
(B) writing a servo pattern on the rotating data recording disk by the read / write head positioned at the position;
(C) reading a servo pattern with a read / write head positioned at the position and detecting an amplitude of an output signal generated by the read / write head;
(D) moving the read / write head from the position along the radial direction;
(E) The servo pattern is read by the moving read / write head from the above position, and the amplitude of the output signal generated by the moving read / write head is generated by the read / write head positioned at the above position. 50-G of the amplitude of the output signal generated _W / 2% detection step (where G _W Is the expected gap width between data recording tracks),
(F) stopping the read / write head when the detection is made;
And (g) writing the servo pattern on the rotating data recording disk with the stopped read / write head.
[0017]
The method of the present invention writes a servo pattern defining a plurality of data recording tracks of a rotating data recording disk included in a disk drive device by a read / write head.
(A) designating a gap width between data recording tracks;
(B) writing a servo pattern defining a plurality of data recording tracks separated by the specified gap width by a read / write head onto a rotating data recording disk;
(C) detecting that the total number of data recording tracks is less than the planned number;
(D) designating an overlapping width of adjacent data recording tracks;
(E) rewriting a servo pattern defining a plurality of data recording tracks overlapping each other by an overlap width by a read / write head onto a rotating data recording disk;
Step (e)
(I) positioning the write / read head at a position along the radial direction of the rotating data recording disk;
(Ii) rewriting the servo pattern on the rotating data recording disk with the read / write head positioned at the position;
(Iii) reading the rewritten servo pattern by a read / write head positioned at the position and detecting an amplitude of an output signal generated by the read / write head;
(Iv) moving the read / write head from the position along the radial direction;
(V) Reading the rewritten servo pattern by the reading / writing head moving from the position, and reading the amplitude of the output signal generated by the moving reading / writing head positioned at the position / Detecting that the amplitude of the output signal generated by the write head is 50 + Y / 2% (where Y is the overlap width);
(Vi) stopping the read / write head when the detection is made;
(Vii) overlaying and rewriting the servo pattern on the rotating data recording disk by the stopped read / write head.
[0018]
The method of the present invention writes a servo pattern defining a plurality of data recording tracks on each of a plurality of data recording surfaces of a rotating data recording disk included in a disk drive device by a read / write head.
(A) designating a gap width between data recording tracks;
(B) writing servo patterns defining a plurality of data recording tracks separated by the specified gap width by the read / write head to a plurality of servo tracks on one data recording surface;
(C) storing a count number indicating the number of servo tracks written on one data recording surface;
(D) repeating steps (b) and (c) until servo patterns are written on all data recording surfaces;
(E) checking whether the total number of data recording tracks written on all data recording surfaces exceeds a predetermined number;
(F) if the answer to step (e) is no, specifying an overlap width of adjacent data recording tracks;
(G) finding a data recording surface including a minimum number of data recording tracks by examining the counts of all data recording surfaces;
(H) rewriting a servo pattern defining a plurality of data recording tracks overlapping each other by the overlap width by the read / write head on the data recording surface found in step (f),
Step (h)
(I) positioning the write / read head at a position along the radial direction of the data recording surface;
(Ii) rewriting the servo pattern on the data recording surface by the read / write head positioned at the position;
(Iii) reading the rewritten servo pattern by a read / write head positioned at the position and detecting an amplitude of an output signal generated by the read / write head;
(Iv) moving the read / write head from the position along the radial direction;
(V) Reading the rewritten servo pattern by the reading / writing head moving from the position, and reading the amplitude of the output signal generated by the moving reading / writing head positioned at the position / Detecting that the amplitude of the output signal generated by the write head is 50 + Y / 2% (where Y is the overlap width);
(Vi) stopping the read / write head when the detection is made;
(Vii) overlaying and rewriting the servo pattern on the rotating data recording disk with the stopped read / write head.
[0019]
The total number of data recording tracks written on all data recording surfaces is checked by referring to the count number of all data recording surfaces.
[0020]
The method of the present invention writes a servo pattern defining a plurality of data recording tracks on each of a plurality of data recording surfaces of a rotating data recording disk included in a disk drive device by a read / write head.
(A) designating a gap width between data recording tracks;
(B) positioning the write / read head at a position along the radial direction of one data recording surface;
(C) setting a counter count value to an initial value;
(D) writing a servo pattern on the data recording surface by the read / write head positioned at the position;
(E) reading a servo pattern with a read / write head positioned at the position and detecting an amplitude of an output signal generated by the read / write head;
(F) moving the read / write head from the position along the radial direction;
(G) The servo pattern is read by the moving read / write head from the position, and the amplitude of the output signal generated by the moving read / write head is adjusted by the read / write head positioned at the position. 50-G of the amplitude of the generated output signal _W / 2% detection step (where G _W Is the specified gap width between data recording tracks),
(H) stopping the read / write head when the detection is made;
(I) stepping the count value;
(J) writing the servo pattern on the data recording surface with the stopped read / write head;
(K) repeating steps (e) to (j) until a servo pattern is written on the entire data recording surface;
(L) selecting the next data recording surface and repeating steps (b) to (k);
(M) checking whether the total number of data recording tracks written on all data recording surfaces exceeds a predetermined number;
(N) If the answer to step (m) is no, specifying the overlap width of adjacent data recording tracks;
(O) finding a data recording surface including a minimum number of data recording tracks by examining the counts of all data recording surfaces;
(P) rewriting a servo pattern defining a plurality of data recording tracks overlapping each other by an overlap width by a read / write head on the data recording surface found in step (o);
Step (p)
(I) positioning the write / read head at a position along the radial direction of the data recording surface;
(Ii) rewriting the servo pattern on the data recording surface by the read / write head positioned at the position;
(Iii) reading the rewritten servo pattern by a read / write head positioned at the position and detecting an amplitude of an output signal generated by the read / write head;
(Iv) moving the read / write head from the position along the radial direction;
(V) The servo pattern rewritten by the reading / writing head moving from the position is read, and the amplitude of the output signal generated by the reading / writing head moving is positioned at the position. Detecting 50 + Y / 2% of the amplitude of the output signal generated by the read / write head (where Y is the overlap width);
(Vi) stopping the read / write head when the detection is made;
(Vii) overlaying and rewriting the servo pattern on the rotating data recording disk by the stopped read / write head.
[0021]
The total number of data recording tracks written on all the data recording surfaces is checked by referring to the above-mentioned count number of all the data recording surfaces.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2 shows three magnetic recording disks 5A, 5B and 5C included in the hard disk drive. Three disks are shown as an example, and more disks can be provided.
[0023]
The upper and lower surfaces of each disk are used as data recording surfaces, so the three magnetic recording disks 5A, 5B and 5C provide data recording surfaces # 1 to # 6. The density of the data recording track in the radial direction of the disk is called TPI (Tracks Per Inch), and the density of the data along the circular data recording track is called BPI (Bits Per Inch). One data read / write head is provided for each data recording surface. In the illustrated case, six data read / write heads are provided. Each data read / write head is attached to a slider assembly, which is attached to the front end of the head support arm. A combination of the head and the slider assembly is called a head / slider assembly. Since the head / slider assembly and head support arm are well known in the art, they are not shown in FIG. The rear ends of the six head support arms are joined together and pivotally attached to the frame of the hard disk drive. The six head support arms are rotated around a pivot point by a voice coil motor (not shown), thereby moving the read / write head along the radial direction of the data recording surface.
[0024]
In the conventional hard disk drive, the number of data recording tracks on each of the six data recording surfaces is the same, and the same track pitch (distance between the track centers of adjacent tracks) is used. Therefore, when the read / write head of the data recording surface # 1 is positioned on the data recording track “X” (Xth track from the outermost or innermost data recording track), the data recording surfaces # 2 to # 6 All the remaining read / write heads are positioned on the data recording tracks “X” of the data recording surfaces # 2 to # 6, as indicated by the dotted lines in FIG. The six data recording tracks “X” are called one data cylinder, and data is read from or written to the data cylinders, ie the six data recording tracks “X” at the same time.
[0025]
The present invention does not use such a data cylinder concept, as will become apparent from the following description.
[0026]
FIG. 3 is a block diagram of a circuit included in the hard disk drive. A spindle motor 13 and a voice coil motor (VCM) 11 that rotate the magnetic recording disk 5 are controlled by a VCM / spindle driver 14. Only one magnetic recording disk 5 is shown to simplify the drawing. Read / write circuit 12 is connected to hard disk control circuit 15, which is also connected to VCM / spindle driver 14. A memory 17 for storing data and control data is connected to the circuit 15 and the main control circuit or MPU 16. The main control circuit 16 controls the VCM / spindle driver 14, the hard disk control circuit 15 and the memory 17. The read / write head is mounted on a slider, and these are called the head / slider assembly 7. The head / slider assembly 7 is attached to the front end of the support arm 4, and the rear end of the support arm 4 is attached to the frame of the hard disk drive.
[0027]
An inner crash stop 18 is mounted on the frame for engaging the head support arm 4 to position the head on the innermost data recording track, and engages the head support arm 4 to position the head on the outermost side. An outer crash stop 19 for positioning on the data recording track is mounted on the frame.
[0028]
FIG. 4A shows one magnetic recording hard disk 5. The recording surface 8 is divided into a plurality of sectors, and a servo pattern is recorded in the portion 6. The annular data recording track 9 is defined by a servo pattern. For simplicity of illustration, only two tracks, the innermost track and the outermost track, and four parts 6 are shown.
[0029]
FIG. 4B shows enlarged portions of the data recording tracks # 1 and # 2 and the servo patterns A and B. Servo patterns A and B are written or recorded as shown in FIG. 4B to define tracks # 1 and # 2 and read by the read / write head to generate a feedback signal. This feedback signal is supplied to the hard disk controller 15. The details of the servo patterns A and B are shown in FIG. Servo pattern A has opposite magnetization directions arranged alternately and servo pattern B has a uniform DC magnetization direction. The hard disk controller 15 positions the center of the head at the track center TC in response to the feedback signal.
[0030]
The present invention eliminates large unused or wasted space between GMR heads on the data recording surface in a conventional track arrangement that uses the same track width, as described in connection with FIG. (A) The hard disk drive has six data recording surfaces # 1 to # 6 as shown in FIG. 2, and (B) read / write head # 1 reads / writes data to / from surface # 1 / Write head # 2 reads and writes data to surface # 2, Read / write head # 3 reads and writes data to surface # 3, and Read / Write heads # 4 to # 6 store data on surfaces # 4 to 6, respectively. Read and write, (C) each head has a head width as shown in Table 1 below, and (D) heads # 1 to # 6 and their respective sliders are mounted on six support arms, respectively. The rear ends of the support arms are connected to each other and pivotally attached to the frame.
[0031]
[Table 1]

The head width represents a dimension along the radial direction of the data recording surface.
[0032]
In the conventional cylinder-type hard disk drive, the number of data recording tracks on all data recording surfaces is the same. In contrast, in the present invention, the number of data recording tracks on one data recording surface such as recording surface # 1 is different from the number of data recording tracks on the other data recording surface such as recording surface # 2, and The gap width between the data recording tracks on the data recording surface is different from the gap width between the data recording tracks on the other data recording surfaces.
[0033]
All the data recording tracks of one data recording surface have the same track width, and all the gaps have the same gap width.
[0034]
All the data recording tracks of the other data recording surfaces have the same track width, and all the gaps have the same gap width.
[0035]
10 and 11 show a flow chart of the operation according to the present invention, and FIGS. 5 to 9 write servo patterns A and B on one data recording surface using its read / write head. The operation is shown.
[0036]
Operation begins at block 31 of FIG. Operation proceeds to block 32 where the MPU 16 selects the first data recording surface # 1. During the operation of writing the servo pattern on the first recording surface # 1, only the head # 1 is operated, and the other heads # 2 to # 6 are not operated.
[0037]
Operation proceeds to block 33 where the MPU 16 and the VCM / spindle driver 14 apply drive current to the VCM 11 until the support arm 4 is stopped by the inner crash stop 18 to move the support arm 4. As a result, the head # 1 is positioned at the reference position P1, that is, the innermost data recording track.
[0038]
Operation proceeds to block 34 where the servo track number is set to one. Operation proceeds to block 35 where a servo pattern is written to servo track number N. In the operation of the block 35, the head # 1 is positioned at the position P1 as shown in FIG. That is, servo patterns A and B are written on the data recording surface # 1, and in this case, the head # 1 on the recording surface # 1 has a head width H of 1.0 μm. _W Have
[0039]
In FIG. 5, a position P1C indicates the center of the head # 1 positioned at the position P1. Servo patterns A1 and B1 are recorded on servo track # 1. In order to write the servo patterns A1 and B1, the read / write circuit 12 in FIG. 3 applies an AC signal for writing the pattern A and a DC signal for writing the pattern B to the head # 1. Only two servo patterns are shown to simplify the figure.
[0040]
Operation proceeds to block 35A, where head # 1 is stopped at position P1, servo patterns A1 and B1 are read, and the amplitude of the output signal of head # 1 is detected by MPU 16 and stored in memory 17 Is done.
[0041]
Operation proceeds to block 36, where head # 1 is moved from position P1 toward the outermost position, and servo pattern A1 and B1 written in block 35 is read as head # 1 moves, The amplitude of the output signal is measured by the MPU 16.
[0042]
Operation proceeds to block 37 where the MPU 16 causes the output signal amplitude to be (50-G) of the amplitude measured in block 35A. _W / 2%) to see if it has been reduced. A value of 100% indicates the full amplitude of the output signal when head # 1 completely overlaps servo patterns A1 and B1 in block 35A. G _W Is the gap width between data recording tracks.
[0043]
In this embodiment, the gap width G _W Is the head width H _W Therefore, the amplitude of the output signal is the value (50-G _W / 2%), that is, (50-5%) = 45%, as shown in FIG. 12, the 1.0 μm head # 1 is separated from the position P1 by a distance (H _W + G _W ) / 2 = move by 0.05 μm.
[0044]
If the answer to block 37 is no, the operation proceeds to block 38 where it checks to see if the head has reached the outer crash stop 19. If the answer to block 38 is yes, operation proceeds to block 43 of FIG. If the answer to block 38 is no, operation returns to block 36. If the answer to block 37 is yes, this indicates that head # 1 has been moved to position P2 in FIG. Operation proceeds to block 39 of FIG. 11, where the movement of head # 1 is stopped at position P2.
[0045]
Operation proceeds to block 40 where the servo track number is incremented to N + 1. Operation proceeds to block 41, where head # 1, stopped at position P2, as shown in FIG. 6, writes servo patterns A2 and B2 over servo patterns A1 and B1, respectively. The distance between the upper ends of the servo patterns A1 and B1 and the position P1C is H _W / 2, ie 0.5 μm, and the distance between the position P1C and the servo patterns A2 and B2 is G _W / 2, and this is the head width H _W Of 5% or 0.05 μm.
[0046]
Operation proceeds to block 42, where the MPU 16 checks whether the number N + 1 is equal to or greater than the planned maximum number of servo tracks (eg, 10,000 servo tracks). If the answer to block 42 is no, the operation returns to block 35A and the operations of blocks 35A-42 are repeated.
[0047]
7 to 9 show servo patterns written in this repetitive operation. In FIG. 7, the head # 1 has a distance D = (H from the position P2 to the position P3. _W + G _W ) / 2 is moved. At position P3, head # 1 writes servo patterns B3 and A3 on servo patterns A2 and B2, respectively. It is apparent that the lower part of the servo pattern A2 is replaced with the servo pattern B3, and the lower part of the servo pattern B2 is replaced with the servo pattern A3. In FIG. 8, head # 1 has a distance D = (H from position P3 to position P4. _W + G _W ) / 2 is moved. At position P4, head # 1 writes servo patterns B4 and A4 on servo patterns B3 and A3, respectively. In FIG. 9, the head # 1 has a distance D = (H from the position P4 to the position P5. _W + G _W ) / 2 is moved. At position P5, head # 1 writes servo patterns A5 and B5 on servo patterns B4 and A4, respectively. It is apparent that the lower part of the servo pattern B4 is replaced with the servo pattern A5, and the lower part of the servo pattern A4 is replaced with the servo pattern B5.
[0048]
In this way, the head # 1 has a distance D = (H _W + G _W ) / 2 is moved toward the outermost position of the data recording surface, and at each position, head # 1 writes a new servo pattern. When head # 1 has written a sufficient number of servo tracks, as indicated by the answer at block 42, the operation of writing servo patterns A and B on the first data recording surface # 1 is completed. . The counter D in the hard disk control circuit 15 or MPU 16 is the distance D = (H _W + G _W ) / 2 is counted, and this value is stored in the memory 17, so that the MPU 16 can know the number of servo tracks written on the recording surface by referring to the counted number.
[0049]
Referring back to FIG. 9, during the read / write operation, head # 1 senses servo patterns A and B and sends a feedback signal to hard disk control circuit 15 via read / write circuit 12 of FIG. Supply. The hard disk control circuit 15 controls the VCM / spindle driver 14 in response to the feedback signal. As a result, the center of the head # 1 is aligned with the boundary between the patterns A2 and B2 and the patterns B3 and A3. Then, the support arm 4 is moved. This boundary is called the track center TC, in this case TC1, and the data recording track # 1 is defined when the data recording disk is rotated in a read / write operation. The width of the data recording track is equal to the width of head # 1 (1.0 μm in this case). The center TC1 of the data recording track # 1 and the center TC2 of the data recording track # 2 will be described. The distance between the centers TC1 and TC2 is 2D = H. _W + G _W In other words, in other words, the head width H _W 10% gap G _W Exists between the data recording tracks # 1 and # 2.
[0050]
Operation proceeds to block 43, where the MPU 16 checks whether servo patterns have been written to all recording surfaces. If the answer to block 43 is no, operation proceeds to block 44 where the MPU 16 selects the next head # 2. The operation returns to the block 33, and the operations of the blocks 33 to 43 are repeated, and the servo patterns A and B are written on the remaining data recording surfaces # 2 to # 6 as described above. In this repeated operation, a servo pattern is written on the second data recording surface # 2 using the second head # 2 having a head width of 0.6 μm. During the operation of writing the servo pattern on the second data recording surface # 2, only the head # 2 is used, and the remaining heads # 1 and # 3 to # 6 are not used. Head width H of head # 2 _W That is, the width of the data recording track is 0.6 μm, and the gap width G _W Is 10% or 0.06 μm. While writing the servo pattern on the third recording surface # 3 using the third head # 3 having a head width of 1.4 μm, only the head # 3 is operated, and the remaining heads # 1, # 2, and # 4— # 6 is not activated. The width of the data recording track is 1.4 μm and the gap width is 10% or 0.14 μm. Answers to block 43 indicate yes by writing servo patterns on all data recording surfaces # 1 to # 6. The data recording surfaces # 1 to # 6 have data track widths and gap widths as shown in Table 2 below. The track pitches of the adjacent data recording tracks on the data recording surfaces # 1 (# 4), # 2 (# 5), and # 3 (# 6) are different from each other.
[0051]
[Table 2]

As the head width increases, the number of tracks on the recording surface decreases and the gap width increases. Recording surfaces # 3 and # 6 have fewer tracks and wider gaps than the remaining recording surfaces. This means that the recording surfaces # 3 and # 6 have a smaller data capacity than the remaining recording surfaces. As described above, the MPU 16 stores the number of servo tracks on the recording surfaces # 1 to # 6. In the next step, the operation proceeds to block 45, where the MPU 16 determines the number of servo tracks (N ₂ ) That is, based on the count value, the total number of data recording tracks on all recording surfaces # 1 to # 6 (N ₁ ) For this purpose, the following equation is used.
[0052]
N ₁ = N ₂ / 2-1
Operation proceeds to block 46, where MPU 16 has a total number N ₁ Is equal to or greater than the expected number “X”. If the answer to block 46 is yes, the operation proceeds to block 48, where the operation ends. If the answer to block 46 is no, the operation proceeds to block 47 where the MPU 16 rewrites the servo pattern so that adjacent data recording tracks overlap each other as shown in FIGS. The operation to start is started.
[0053]
Referring to FIGS. 13 and 14, the operation begins at block 51. Operation proceeds to block 52 where the MPU 16 specifies Y = 0. As the following equation shows, Y represents a value that specifies the overlapping width of adjacent data recording tracks.
[0054]
Overlap width = head width (H _W ) X Y (%)
When Y = 0, as shown in FIG. 15A, the overlap width between adjacent data tracks # 1 and # 2 is zero and the gap between data tracks # 1 and # 2 is zero (G _W = 0). In other words, as shown in FIG. 15A, the servo pattern is rewritten so that the data recording tracks # 1 and # 2 are adjacent to each other without overlapping and without generating a gap.
[0055]
The reason for initially specifying the value Y = 0 in block 52 is that the data recording track of the recording surface containing the minimum number of servo tracks and hence the minimum number of data recording tracks has the widest track width, even if the data tracks This is because, even if the gap between them is reduced to zero, in the widest data track, the probability of error occurrence and the S / N ratio are low.
[0056]
Operation proceeds to block 53 where the MPU 16 selects the head of the data recording surface that contains the minimum number of servo tracks. As described above, the MPU 16 records the number of servo tracks written on the data recording surfaces # 1 to # 6 in the counter, and the MPU 16 records the recording surface including the minimum number of data recording tracks, for example, the recording surface # 3 can be selected. Operation proceeds to block 54 where head # 3 of recording surface # 3 is moved to a reference position. In block 58, the moving distance of the head # 3 from the positions P1 to P2 and from P2 to P3 based on the parameter Y = 0 is the distance H. _W Note that the same operation as that of blocks 33 to 42 in FIGS. 10 and 11 is performed in blocks 54 to 63 except that / 2 is selected and data recording tracks # 1 and # 2 having no overlap are formed. I want to be.
[0057]
After the servo pattern has been rewritten on the entire surface of data recording surface # 3, operation proceeds to block 64 of FIG. 14, where MPU 16 performs the same operation as block 45 of FIG. Number of servo tracks 1 to # 6 (N ₂ ) That is, based on the count value, the total number of data recording tracks on all recording surfaces # 1 to # 6 (N ₁ ) As described above, the following equation is used in this operation.
[0058]
N ₁ = N ₂ / 2-1
Operation proceeds to block 65, where MPU 16 has a total number N ₁ Is equal to or greater than the expected number “X”. If the answer to block 65 is yes, the operation proceeds to block 71, where the operation ends. If the answer to block 65 is no, the operation proceeds to block 66, where the MPU 16 checks whether all recording surfaces # 1 to # 6 have been rewritten. If the answer in block 66 is no, the operation proceeds to block 67, where the MPU 16 selects the recording surface that contains the next lowest servo track number. In this case, the recording surface # 6 is selected. The reason is that this recording surface is written by the head # 6 having a head width of 1.4 μm and the number of data tracks is smaller than the remaining recording surfaces.
[0059]
The operation returns to block 54 to rewrite servo patterns A and B, and the operations of blocks 54-65 are repeated. If the answer in block 65 is no and the answer in block 66 is no, the servo pattern is rewritten on the remaining recording surface, eg, # 1 or # 4. After repeating the above operation, if the answer to block 65 is no and the answer to block 66 is yes, this forms a non-overlapping data recording track as shown in FIG. As shown, the total number of data recording tracks on all data recording surfaces is less than the predetermined number “X” even though servo patterns are rewritten on all data recording surfaces # 1 to # 6. .
In this case, operation proceeds to block 68 where the MPU 16 changes the overlap width value from Y to a new value Y + 10. Explaining the operation of block 68, this block 68 selects one of the next values to perform the next operation each time the answer of block 66 is yes.
[0060]
Case 1 operation: Y = 0
Case 2 operation: Y = 10
Case 3 operation: Y = 20
That is, block 68 increases the value of Y in response to the answer yes to block 66.
[0061]
The operation of case 1 is illustrated in FIG. 15A, where the head is distanced so that data recording tracks # 1 and # 2 are formed or defined without overlapping each other and without gaps. D ₁ = H _W Servo patterns A and B are rewritten by being moved by / 2. The operation of case 2 is illustrated in FIG. 15B, where Y = 10 forms or defines data recording tracks # 1 and # 2 that are overlapped with each other by 10% of the head width. Indicates that the servo pattern is rewritten. Recall the following expression that expresses the overlap width.
[0062]
Overlap width = head width (H _W ) X Y%
To ensure that the data recording tracks overlap by 10%, the head is D ₂ = H _W / 2- (H _W X 0.05). That is, the head is moved a distance equal to 45% of the head width. The operation of case 3 is illustrated in FIG. 15C, where servo patterns A and B are regenerated to form or define data recording tracks # 1 and # 2 that overlap each other by 20% of the head width. Written. In order to overlap the data recording tracks by 20%, the head is D ₃ = H _W / 2- (H _W X0.1) is moved by a distance. That is, the head is moved by a distance equal to 40% of the head width.
[0063]
In this way, the MPU 16 checks whether or not the total number of data recording tracks on all the data recording surfaces has reached the predetermined number “X” in the blocks 65 and 66, and if not, the MPU 16 Increases the overlap width to the next value and rewrites the servo pattern with this new value. As shown in block 69, in the embodiment of the present invention, Y = 20 is the maximum value of overlap, so if block 69 is answered yes, the operation proceeds to block 70. This means that the distance D is formed so as to form data recording tracks that overlap each other by 20% as shown in FIG. ₃ The total number of data tracks on all recording surfaces # 1 to # 6 did not reach the expected number “X” even though the head was moved only and servo patterns were rewritten on all recording surfaces. It shows that. Block 70 indicates that the result was Fail and the operation ends at this block 70.
[0064]
According to the experimental analysis by the inventor of the present invention, the probability of proceeding to block 70 is less than 1% and the probability that a desired number of data tracks will be written during case 1 or case 2 operation is greater than 99%. I understood.
[0065]
FIG. 16A shows a data writing system according to the present invention. It is assumed that three magnetic recording disks 5A, 5B and 5C are mounted on the spindle motor 13 to provide six data recording surfaces # 1 to # 6.
[0066]
As indicated by arrows 24A to 24F, a start address is assigned to the outermost data recording track of the first data recording surface # 1, and the address of the first recording surface # 1 is the innermost from the outermost data recording track. Data recording tracks are allocated in order. The address next to the address of the innermost data recording track of the first data recording surface # 1 is assigned to the outermost data recording track of the second data recording surface # 2, and the second data recording surface # 2 Addresses are assigned in order from the outermost data recording track to the innermost data recording track, and so on.
[0067]
Data is written in the direction from the outermost data recording track of the first recording surface # 1 to the innermost data recording track as indicated by the arrow 24A, and then the data is recorded in the second recording direction as indicated by the arrow 24B. The data is written in the direction from the outermost data recording track of the surface # 2 toward the innermost data recording track, and then the data is transmitted from the outermost data recording track of the third recording surface # 3 as indicated by the arrow 24C. Written in the direction toward the inner data recording track, and so on.
[0068]
FIG. 16B shows a conventional cylinder type data writing method. Data is written in the direction of arrow 25A, then data is written in the direction of arrow 25B, data is then written in the direction of arrow 25C, and so on.
[0069]
As shown in Table 2, in the present invention, the number of data recording tracks on each of the data recording surfaces # 1 to # 6 is different based on the difference in the width and gap of the data recording tracks on each of the data recording surfaces. The data writing method shown in FIG.
[0070]
【The invention's effect】
According to the present invention, when the data recording tracks for the GMR head are formed with a uniform track pitch, the first problem described above is that an unnecessary and useless space is formed between the data recording tracks of the GMR head. Solve the point.
[0071]
Furthermore, the present invention solves the second problem described above as described below.
In the conventional system in which the track pitch is fixed, the fluctuation of the feedback signal is as follows as described above.
Track width (μm) 0.6 1.0 1.4
Track pitch (μm) 1.6 1.6 1.6
10% of track pitch (μm) 0.16 0.16 0.16
Feedback signal fluctuation 26.7% 16.0% 11.4%
In the system of the present invention in which the track pitch varies depending on the track width, the variation of the feedback signal is constant as follows.
Track width (μm) 0.6 1.0 1.4
Track pitch (μm) 0.66 1.1 1.54
10% of track pitch (μm) 0.066 0.11 0.154
Feedback signal fluctuation 11.0% 11.0% 11.0%
[Brief description of the drawings]
FIG. 1 illustrates the problems caused by arranging GMR heads using conventional data tracks having a uniform track pitch.
FIG. 2 is a diagram showing three magnetic recording disks for explaining the concept of a cylinder used in a conventional hard disk drive device.
FIG. 3 is a block diagram of a circuit included in the hard disk drive device.
FIG. 4 is a diagram showing a data recording track defined by a data recording disk and a servo pattern.
FIG. 5 is a diagram showing steps of writing a servo pattern according to the present invention.
FIG. 6 is a diagram showing steps of writing a servo pattern according to the present invention.
FIG. 7 is a diagram showing steps of writing a servo pattern according to the present invention.
FIG. 8 is a diagram showing steps of writing a servo pattern according to the present invention.
FIG. 9 is a diagram showing steps of writing a servo pattern according to the present invention.
FIG. 10 shows a flowchart according to the present invention for writing a servo pattern.
FIG. 11 shows a flow chart according to the present invention for writing servo patterns.
FIG. 12 shows the movement of the head from one position to the next position according to the present invention.
FIG. 13 shows a flowchart according to the invention for rewriting a servo pattern.
FIG. 14 shows a flowchart according to the invention for rewriting a servo pattern.
FIG. 15 is a diagram showing an operation for rewriting a servo pattern according to the present invention.
FIG. 16 is a diagram showing an address system of a hard disk drive device and an address system of a conventional hard disk drive device.
[Explanation of symbols]
1,2,3 ... head,
4 ... support arm,
5 ... disc,
7: Head support arm,
11 ... VCM
12: Read / write circuit,
13 ... spindle motor,
14 ... VCM / spindle driver,
15: Hard disk control circuit,
16 ... MPU,
17 ... Memory

Claims (6)

In a method of writing a servo pattern with a GMR head so as to define a plurality of data recording tracks having different track widths and gap widths on each of recording surfaces of a rotating data recording disk included in a disk drive device,
(A) positioning the write / read head at a position along the radial direction of the rotating data recording disk;
(B) writing a servo pattern on the rotating data recording disk by the GMR head positioned at the position;
(C) reading the servo pattern with the GMR head positioned at the position and detecting the amplitude of the output signal generated by the GMR head ;
(D) moving the GMR head from the position along the radial direction;
Reading the servo pattern by the GMR head during movement from (e) above positions, the amplitude of the output signal generated by the GMR head in the movement, generated by the GMR head has been positioned to the position and detecting that became 50-G W / _2% of the amplitude of the output signal (here the G _W is the gap width of the planned between the data recording track each other),
(F) stopping the GMR head when the detection is made;
(G) A servo pattern writing method including the step of writing the servo pattern on the rotating data recording disk by the stopped GMR head . In a method of writing a servo pattern with a GMR head so as to define a plurality of data recording tracks having different track widths and gap widths on each of recording surfaces of a rotating data recording disk included in a disk drive device,
(A) designating a gap width between the data recording tracks;
(B) writing a servo pattern defining a plurality of data recording tracks separated by the specified gap width by the GMR head onto the rotating data recording disk;
(C) detecting that the total number of the data recording tracks is less than a predetermined number;
(D) designating an overlapping width of adjacent data recording tracks;
(E) rewriting a servo pattern defining a plurality of data recording tracks overlapped with each other by the GMR head onto the rotating data recording disk;
The step (e)
(I) positioning the write / read head at a position along the radial direction of the rotating data recording disk;
(Ii) rewriting a servo pattern on the rotating data recording disk by the GMR head positioned at the position;
(Iii) reading the rewritten servo pattern by the GMR head positioned at the position and detecting an amplitude of an output signal generated by the GMR head ;
(Iv) moving the GMR head from the position along the radial direction;
(V) by the GMR head during the movement from the position reading servo patterns rewritten above, the amplitude of the output signal generated by the GMR head in the movement, the GMR which has been positioned to the position Detecting that it is 50 + Y / 2% of the amplitude of the output signal generated by the head (where Y is the overlap width);
(Vi) stopping the GMR head when the detection is made;
And (vii) a servo pattern writing method including the step of superimposing and rewriting the servo pattern on the rotating data recording disk by the stopped GMR head . In a method of writing a servo pattern with a GMR head so as to define a plurality of data recording tracks having different track widths and gap widths on each of recording surfaces of a rotating data recording disk included in a disk drive device,
(A) designating a gap width between the data recording tracks;
(B) writing servo patterns defining a plurality of data recording tracks separated by the specified gap width by the GMR head to a plurality of servo tracks on one data recording surface;
(C) storing a count number indicating the number of servo tracks written on the one data recording surface;
(D) repeating the steps (b) and (c) until the servo pattern is written on all data recording surfaces;
(E) checking whether the total number of data recording tracks written on all the data recording surfaces exceeds a predetermined number;
(F) if the answer to step (e) is no, specifying the overlap width of adjacent data recording tracks;
(G) finding a data recording surface including a minimum number of data recording tracks by examining the counts of all the data recording surfaces;
(H) rewriting servo patterns defining a plurality of data recording tracks overlapped with each other by the GMR head on the data recording surface found in step (f),
Step (h) above
(I) positioning the write / read head at a position along the radial direction of the data recording surface;
(Ii) rewriting a servo pattern on the data recording surface by the GMR head positioned at the position;
(Iii) reading the rewritten servo pattern by the GMR head positioned at the position and detecting an amplitude of an output signal generated by the GMR head ;
(Iv) moving the GMR head from the position along the radial direction;
(V) by the GMR head during the movement from the position reading servo patterns rewritten above, the amplitude of the output signal generated by the GMR head in the movement, the GMR which has been positioned to the position Detecting that it is 50 + Y / 2% of the amplitude of the output signal generated by the head (where Y is the overlap width);
(Vi) stopping the GMR head when the detection is made;
And (vii) a servo pattern writing method including the step of superimposing and rewriting the servo pattern on the rotating data recording disk by the stopped GMR head . 4. The servo pattern writing method according to claim 3, wherein the total number of data recording tracks written on all the data recording surfaces is checked with reference to the count number of all the data recording surfaces. . In a method of writing a servo pattern with a GMR head so as to define a plurality of data recording tracks having different track widths and gap widths on each of recording surfaces of a rotating data recording disk included in a disk drive device,
(A) designating a gap width between the data recording tracks;
(B) positioning the write / read head at a position along the radial direction of one data recording surface;
(C) setting a counter count value to an initial value;
(D) writing a servo pattern on the data recording surface by the GMR head positioned at the position;
(E) reading the servo pattern with the GMR head positioned at the position and detecting the amplitude of the output signal generated by the GMR head ;
(F) moving the GMR head from the position along the radial direction;
By the GMR head during movement from (g) above position read the servo pattern, the amplitude of the output signal generated by the GMR head in the movement, generated by the GMR head has been positioned to the position and detecting that became 50-G W / _2% of the amplitude of the output signal (here the G _W is the specified width of the gap between the data recording track each other),
(H) stopping the GMR head when the detection is made;
(I) stepping the count value;
(J) Overwriting the servo pattern on the data recording surface by the stopped GMR head ;
(K) repeating the steps (e) to (j) until the servo pattern is written on the entire data recording surface;
(L) selecting the next data recording surface and repeating steps (b) to (k) above;
(M) checking whether the total number of data recording tracks written on all the data recording surfaces exceeds a predetermined number;
(N) If the answer to step (m) is no, specifying an overlap width of adjacent data recording tracks;
(O) finding a data recording surface including a minimum number of data recording tracks by examining the counts of all the data recording surfaces;
(P) rewriting servo patterns defining a plurality of data recording tracks overlapped with each other by the GMR head on the data recording surface found in step (o),
Step (p) above is
(I) positioning the write / read head at a position along the radial direction of the data recording surface;
(Ii) rewriting a servo pattern on the data recording surface by the GMR head positioned at the position;
(Iii) reading the rewritten servo pattern by the GMR head positioned at the position and detecting an amplitude of an output signal generated by the GMR head ;
(Iv) moving the GMR head from the position along the radial direction;
(V) by the GMR head during the movement from the position reading servo patterns rewritten above, the amplitude of the output signal generated by the GMR head in the movement, the GMR which has been positioned to the position Detecting that it is 50 + Y / 2% of the amplitude of the output signal generated by the head (where Y is the overlap width);
(Vi) stopping the GMR head when the detection is made;
And (vii) a servo pattern writing method including the step of superimposing and rewriting the servo pattern on the rotating data recording disk by the stopped GMR head . 6. The servo pattern writing method according to claim 5, wherein the total number of data recording tracks written on all the data recording surfaces is checked with reference to the count number of all the data recording surfaces. .

Images