JPS584376B2 - Magnetic tape control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic tape controller (MTC) in a computer system.

A computer system with the following configuration: a central processing unit (CPU), a channel device connected to the CPU, and a magnetic tape control device (M
There are a large number of computer systems that consist of a magnetic tape unit (TC) and one or more magnetic tape units (MTU) connected to the MTC.

However, since there are a wide variety of CPUs and MTUs, the number of combinations of the above configurations is extremely large.

For example, if we look at MTU, tape speed is 20
There are at least three types: 0IPS, 125IPS, and 75IPS, followed by recording density of 6250RPI and 1600R.
There are at least three types: PI and 800RPI.

Regarding the channel devices, there is a selector channel (SLC);
), there is a block multiplexer channel (BMC) with a larger throughput time.

Furthermore, there are various types of CPUs, from low-speed small ones to high-speed large ones.In this case, the MTU
Although it is preferable to match the optimum MTC depending on the type of CPU or Nayanel device, this is extremely difficult in practice.

Therefore, an object of the present invention is to provide an MTC that can combine a wide variety of MTUs, channel devices, etc. in the same MTC.
The goal is to provide the following.

In accordance with the above object, the present invention provides a determination means for determining the operation mode in which the MTU should operate, and a switching means for switching the operation mode in which the MTC should operate according to the MTU.
It is characterized by the addition of

The present invention will be explained below with reference to the drawings.

FIG. 1 is a block diagram of a general computer system to which the present invention can be applied.

In the figure, 11 is a CPU, 12 is a channel device, and 13 is a CPU.
is MTC, 14-0, 14-1, 14-2...
... are various MTUs.

For now, MTU14-0 has 6250RPI, 125
It is assumed that an IPS operating mode is required, and MTUs 14-1 and 14-2 are required to have an operating mode of 1600 RPI, 125 IPS, and 6250 RPI, 75 IPS, respectively.

Therefore, looking at MTU14-O, its data transfer rate is 781 (=6250XI.25)K. B/S, it is impossible to connect to the channel device 12 in selector channel (SLC) mode, and requires connection in block multiplexer mode (BMC mode).

The other MTUs 14-1 and 14-2 are 469 KB/S and 200 KB/S, respectively, and can be connected to the channel device 12 in selector channel (SLC) mode.

Note that the selector channel (SLC) mode is applied when the data transfer rate is 600 KB/S or less.

Therefore, for the MTU14-0, MTC13:
BMC mode must be selected for upper channel device 12, while MTU 14-1 and MTU 14
-2, SLC mode should be selected.

Note that the channel device 12 in FIG. 1 is a BMC, and it is assumed that the BMC can also operate in the SLC mode.

In the above case, MTC13 is MTU14-014-
1, 14-2...... The operation mode was selected according to the data transfer speed of each of the CPUs.
11 should also be selected for its operating mode.

In other words, the CPU 11 is not always large in size and operates at high speed, and depending on the degree of functionality required of the CPU, the CPU
In some cases, the data transfer speed of II is low, so in such cases, MTC13 is not in BMC mode but in SL mode.
C mode should be selected.

In any case, MTU14-0, 14-1, 14-2
. . . and since it is difficult and unsuitable to appropriately select the MTC 13 for each operating mode requested by the CPU 11, the MTC 13 switches its operating mode by itself depending on at least two operating modes. It would be extremely convenient if possible.

The MTC 13 can switch the operating mode by itself, for example, by switching the clock frequency into at least two stages, high and low.

FIGS. 2 and 3 shown below are based on the present invention.
12, 13 and 14-0 are the already mentioned channel devices, MTC and MTU, respectively;
Inside the MTC 13, flip-flop circuits (F-F) 22 and 2 based on the present invention are installed in place of the existing control circuit 21.
3, a discrimination circuit 24, and a detection circuit 25 are added.

The detection circuit 25 sends out various signals to the control lines M1, M2, R1, I1, R2 and 2 based on information from the CPU and MTU.

The control line M1 transmits a signal (“1”) indicating that the CPU 11 should operate in the BMC mode, and the control line M2 transmits a signal (“1”) indicating that the CPU 11 should operate in the BMC mode.
The control lines R1 and R2 transmit a signal indicating the recording density (for example, 6250 RPI) of each MTU, and the control line 1 and (2) transmits a signal indicating what tape speed (for example, 125 IPS) each of the MTUs is.

Therefore, in the above example, MTU is 6250RPI, 125I
When operating at PS, that is, when operating at 781 KB/S, the AND condition of AND circuit A1 in discrimination circuit 24 is satisfied, and the output of flip-flop circuit 22 becomes "1".
'', and the control circuit 21 maintains the BMC mode.

On the other hand, when operating at either 6250 RPI or 125 IPS, that is, when operating at 600 KB/S or less, the AND condition of the AND circuit A2 in the discrimination circuit 24 is satisfied, and the output of the flip-flop circuit 23 is "
1'' is maintained, and the control circuit 21 maintains the SLC mode.

FIG. 3 shows a configuration where all MTUs have the same tape speed.

However, the same reference numbers are given to the same components as in FIG. 2.

In this figure, controls #Rx, R2 and R3 are respectively
For example 6250RPI, 1600RPI and 800R
A signal (“1”) representing PI is transmitted.

Therefore, at 6250 RPI, the output of flip-flop 22 becomes "I", while at 1600 RPI or 800
When in RPI, the output of the flip-flop 23 becomes "1", and the MTC 13 becomes BMC mode and SLC mode, respectively.
Select mode.

As explained above, according to the present invention, MTU or C
The same MTC performs the operation according to the operation mode requested by the PU.
can choose for themselves and obtain a highly efficient computer system.

[Brief Description of the Drawings] Fig. 1 is a block diagram showing an example of a general computer system to which the present invention is applied, and Fig. 2 is a block diagram showing an example of a general computer system to which the present invention is applied.
FIG. 3 is a block diagram showing another embodiment of the MTC according to the present invention. In the figure, 11 is the CPU, 12 is the channel device, 13 is the MTC, 14-ro, 14-1, 14-2... is the MTU, 21 is the control circuit, 24 is the discrimination circuit, and 25 is the detection circuit. be.

Claims (1)

[Claims] 1. A computer system comprising a magnetic tape controller (MTC) controlled by a central processing unit (CPU) via a channel device, and a magnetic tape device (MTC) controlled by the magnetic tape controller (MTC). In the magnetic tape controller (MTC), the central processing unit (CPU) and the magnetic tape unit (MTU)
) has a discrimination circuit that receives operation mode type information sent from one or both of the operating modes and discriminates the type, and according to the discrimination result of the discrimination circuit, the magnetic tape controller (MTC) A magnetic tape control device characterized by switching operation modes.