JPS5857607A - Recording system of magnetic tape - Google Patents

Abstract

PURPOSE:To give an access with high efficiency to the desired stripe, by providing the discrimination information and the gap information at the head of a stripe-shaped storage region and selecting the discrimination information with an input/output device and within the reading period of the gap information. CONSTITUTION:A gasp G is provided at each head part of data segments SG1- including a data region DT and an error correction code ECC in order to secure the discrimination information ID and the time to analyze the information ID. A magnetic tape device SMT is connected to a processor CC via an input/output controller IOC. The processor CC feeds the number of the stripe stroging a desired data to the device IOC. The device IOC analyzes the information ID which is obtained by driving the device SMT to obtain a desired result and then reads out the data DT following the desired one to transfer it to the processor CC. As a result, an access is possible with high efficiency to a desired stripe, and the load of the processor CC is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for recording stripes on a magnetic tape, and more particularly to a data recording method that reduces the time it takes to read information from a magnetic tape.

Generally, recording in stripes on a magnetic tape is performed in an oblique manner as shown in FIG.

When the magnetic tape 1 is wound around a magnetic head (a substantially cylindrical head), data is recorded in a data area 2. While the magnetic tape read control detects the servo track 3, it searches a designated instruction track (on which a stripe number is recorded) 4 to determine the target data area.

When using magnetic tape in data processing systems.

This is because there is a speed difference between the reading time of striped information and the processing time inside a processing device such as a computer.

Conventionally, as shown in FIG. 2, the contents of the magnetic tape device 8MT are first transferred to the magnetic disk device DK, and then the processing device CC is processed.

The magnetic disk device DK was accessed to perform processing such as reading information. An input/output control device SDC (8
tragingDisk Controller
), and this input/output control device SDC supports the magnetic tape control function MTC and the magnetic disk control function DKC, and accesses the magnetic tape device SMT and magnetic disk device DK, respectively, to control the magnetic tape device SM'l'' and the magnetic disk device. Information is transferred between DKs.In this conventional information processing method, the recording format of the magnetic tape was configured as shown in Figure 3.The recording format of the conventional magnetic tape in Figure 3 is 1. The data area on one stripe (striped data area 4 in FIG. 1) includes a plurality of segments SG, ~S
Gn, each segment is divided into data DT, :r-
Consists of error correction code ECC part, one segment 8M
The error correction code section 1 CC is ECC1.
, ECC2 and their respective section marks 8M. Therefore, when reading the contents of a magnetic tape that has been completely recorded in stripes, there is a processing time required to temporarily store the contents on the magnetic disk in order to follow the information processing of the processing device d. The purpose of the present invention is to solve such problems.

The objective is to secure an area for data identification and time to analyze its identification information fM during data configuration of a data area on a magnetic tape.

To achieve the above object, the present invention provides a system for recording data in stripes on a magnetic tape, in which nine gaps are provided for identification information at the beginning of the data area of each stripe.

When requesting the transfer of data from a processing device (conbeater, etc.) to a magnetic tape device via an input/output control device, the input/output control device reads the identification information and then reads out the gap portion. The method is characterized in that the identification information is analyzed. The present invention will be described in detail below using examples.

FIG. 4 schematically shows a system configuration according to the present invention.

The processing unit CC can access the magnetic tape SMT via the input/output control unit IOC. FIG. 5 is a diagram showing the magnetic tape recording method of the present invention, in which a gap () is provided before the data segment (SO3-) in the data area ST to ensure time for analyzing the identification information iD, identification information, and TD. It is a provision. This identification information ID includes file information (generally, one magnetic tape has multiple files, information that identifies each file unit), physical stripe (each stripe is given a series of numbers, and the memory address is ), logical stripes (a series of numbers assigned to the same attribute when configuring multiple stripes as one file), etc. are stored, and these identification information D are stored by the input/output controller IOC. By first reading and analyzing it, it is possible to determine whether or not the correct data area is being read.

That is, in the conventional recording method, the input/output control device attempts to transfer data according to instructions from the processing device CC.

Even if the track of the stripe number is searched and the target stripe is found, it cannot be determined whether the data in the data area is correct or not, and the data is transferred to the processing device CC.

Therefore, even if the nature of the data to be transferred is unknown and the data is abnormal, it will not be transferred to the processing device CC.If the processing device CC determines that the data is abnormal, processing such as a serial try will be performed under the control of the CC. This causes an increase in the load on the CC. Therefore, the present invention uses the identification information ID at the front of the data area ST on the magnetic tape.

The suitability of data transfer is determined by the input/output control device IOC. Then, in order to secure time for the judgment, there is a gap (
A cap part G is provided.

The operation shown in FIG. 4 will be explained based on the recording method shown in FIG. 5.

First, a magnetic tape device S that directly reads and writes magnetic tape.
MT is connected to the input/output control device IOC, and also ]'O
Since C is connected to the processing unit CC by a channel.

The processing device CC sends the stripe number in which desired data is stored to the input/output control device 10C. Then, the input/output control unit IOC' drives the magnetic tape control unit [SMT to position the magnetic head at the target stripe, and upon completion of the process, the magnetic tape control unit SMT sends data area identification information D
is transferred to the input/output control unit IOC. Input/output control device I
The OC analyzes this identification information and skips (ignores) the gap information sent to the primary.As a result of the analysis, if the data is required by the processing device CC, it continues after the first gap G. Only the part of the data that is transferred is transferred to the processing device CC. If the magnetic tape device SM
If the input/output control unit IOC determines that the data transferred from T is not the appropriate data, it tries to read the data again, increasing the reliability of the data transferred to the processing device CC and reducing the burden on the processing device CC. let

FIG. 6 is a diagram showing the processing of the above-mentioned input/output control device over time. Magnetic tape control device SM on the vertical axis
The horizontal axis shows the read data contents of the input/output control device T.

The processing time t of C is shown, and for each data TD, G, and DT, the gap G that is transferred at time A when the ID is analyzed and processed is ignored, and the gap G that is transferred after reading the gap from the SMT is Processing B begins in which the incoming data DT is transferred to the processing device CC.

For example, assume that the data transfer rate between the magnetic tape control device and the input/output control device is 1.7 M Byte/S, the processing speed of the input/output control device is 180 ns/instruction, and the analysis of the identification information ID requires 280 steps and approximately In short, the gap 0 is about 85 bytes.

As explained above, according to the present invention, when data is transferred from a magnetic tape recorded in stripes to a processing device +W, identification information and gaps are provided in the data area of the magnetic tape. In the input/output control device, it is possible to analyze the identification information, reduce the burden on the processing device, and increase the reliability of the data.

[Brief explanation of the drawing]

Fig. 1 is a diagram of a magnetic tape format recorded in stripes, Fig. 2 is a conventional system configuration diagram, Fig. 3 is a diagram explaining a conventional magnetic tape recording method, and Fig. 4 is a diagram according to the present invention. A system configuration diagram, FIG. 5 is an explanatory diagram of the magnetic tape recording method of the present invention, and FIG. 6 is an explanatory diagram of the processing time of the input/output control device. CC: Control device (computer, etc.). IOC: Input/output control unit. SMT: Magnetic tape controller. 1: Magnetic tape, ST: Data area. ■D: Identification information, DT: Data. G: Gap, ECC: Error correction code.

Claims (1)

[Claims] In a method of recording data in stripes on a magnetic tape, identification information is provided at the beginning of the data area of each stripe. After the input/output control device reads out the identification information when a processing device (such as a computer) requests data transfer to the magnetic tape device via the input/output control device. A magnetic tape recording method characterized in that the identification information is analyzed within a time period for reading out the gap portion.