JPH0449184B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a file information search device that searches information stored in a file at high speed.

[Prior art]

Flexible disks are often used as files for storing information in office computers, personal computers, and the like.
Hereinafter, the flexible disk will be abbreviated as disk. FIG. 1 shows a disk loaded into a disk drive device. As shown in Figure 1, the disk is
It has a plurality of tracks T ₁ to T _M , and the tracks
T ₁ to T _M have a plurality of sectors S, and normal writing and reading to and from a disk is performed in units of sectors. The index hole IH detects the relative position of the rotating disk.

In order to manage multiple programs and data as files on a disk, file management information such as the unique name of each file and the location on the disk where the main body of the file is stored is collectively stored as a directory, for example, on the disk. It is held on the top outermost track _T1 . FIG. 2 shows an example of a directory. In Figure 2, the file name FN is three characters, followed by the track address on the disk where the file itself is stored.
TA, sector address SA, file size SZ
are recorded. To access the file,
First, move the head of the disk drive with the disk loaded to the track where the directory is stored.
After moving to T ₁ , read the directory into the computer's memory, and obtain the positions TA and SA of the file itself on the disk from the management information of the file you want to access in the directory. moreover,
By moving the head to these TA and SA positions, you can read and write the file itself.

When accessing the files mentioned above, in the case of flexible disks, the average head travel time is
It takes about 150ms to 300ms, and in applications where multiple files need to be accessed frequently, this time cannot be ignored. Using the case of a 5.25-inch mini flexible disk as an example, we will analyze the time it takes to finally read out the necessary information. If it takes 12 msec to move the head between tracks, 480 msec for 40 tracks, 20 msec.
If it is a truck, it takes 240 msec. Immediately after that, it takes about 50 msec for the head vibration to subside (head settling time) and about 40 msec for the head to press against the disk surface (head load time). In order to read the actual data, the disk must be at least 1
Time to rotate (maximum approx. 20 msec, average approx. 100 msec)
m seconds) must be added. In other words, the maximum access time is ACTMAX=480+50+40+200=770
m seconds average ACTAVE=240+50+40+100=430
m seconds.

When accessing a file in the example shown above that has a directory as shown in Figure 2 on the outermost periphery of the disk, assuming that the head is initially on any track, on average it takes After ACTAVE, it will take an average of ACTAVE time to start reading the file itself. In other words, every time a file in a disk is accessed by file name, it takes ACTAVE x 2 on average until the file itself is read.
It will take some time.

When accessing the above files, in order to avoid reading the directory, when the power is turned on or the computer system is started,
One possible method is to load the entire directory into the computer's internal memory, but in the case of a flexible disk drive, the loaded disk can be easily removed and another disk loaded, so the entire directory can be loaded into the computer's internal memory. There was an inconvenience that the loaded directory and the actual directory on the disk did not match, making files inaccessible or destroying the directory on the disk.

[Purpose of the invention]

An object of the present invention is to provide a means for reducing the frequency of access to a file management information section (directory) held in a medium such as a flexible disk in a file information search device.

[Summary of the Invention] In order to achieve the above-mentioned object, the present invention detects whether a loaded disk is a newly loaded disk or a disk that has been loaded previously, in conjunction with a disk drive device. A means or a means by which users can input data, and retaining that information.
The computer to which the disk is connected
means for the CPU to read the retained information.

[Embodiments of the invention]

The principle of the present invention will be explained with reference to the block diagram of FIG. In FIG. 3, 1 is a disk drive device;
2 is a disk loaded in the drive device; 3 is a computer main body; 4 is detection means or input means for determining whether the disk loaded in the drive device is a newly loaded disk; and 5 is information obtained in step 4. The data can be read from the CPU of the computer main body 3 using the holding means.

The file access procedure in the configuration of FIG. 3 will be explained with reference to the flowchart of FIG. In the following description, 4 is a switch input circuit that the user presses when loading a new disk.

Before the user loads the disk 2 into the drive device 1 and inputs a command to the computer 3 to use the disk 3, the switch 4 is pressed. This information is held in the holding means 5 as, for example, "1". When starting to access a file stored in the disk 2, the program of the computer 3 that controls the file access first reads the contents of the information holding means 5, as shown in FIG.
If this information is "1", the disk loaded in the drive device 1 is a newly loaded disk, so all the directory information of the disk is
The data is read and saved in the memory of the computer 3.
Thereafter, the contents of the information holding means described above are rewritten to, for example, "0". Conversely, in FIG. 4, if the result of reading the contents of the information holding means 5 is "0", all directory information is stored in the memory within the computer 3, so there is no need to read the directory information.

Therefore, when accessing the file for the first time after loading the disk 2 into the drive device 1, an operation and time to read the directory information is required, but when accessing the file thereafter, there is no need to read the directory information anew, and the above-mentioned File access time ACTAVE×2 can be saved. At this time, since the switch input circuit 4 and its information holding means 5 guarantee that the loaded disk is the same as the disk at the time of previous access, the directory information in the memory and the actual It is possible to prevent accidents such as inaccessibility or directory destruction due to discrepancies with the directory.

An embodiment of the present invention will be described below with reference to FIG. FIG. 5 is a detailed circuit diagram of the switch circuit 4 and data holding means 5 shown in the block diagram of FIG.
In Fig. 5, 6 is a switch, and 7 is a switch 6.
8 is a RS-FF (set/reset flip-flop), 9 is a buffer, 10 is a signal line connected to the data bus of the computer 3, 11
is an address decoder for selecting the data holding means 5; 12 is an address bus of the computer 3;
14 is a delay circuit. FIG. 6 shows the timing chart of FIG. 5. When the flexible disk 2 is loaded into the drive device 1 and the switch 6 is pressed (indicated by the arrow in Fig. 6), the set input S of the RS-FF8 is activated.
falls to “Low”, so the output Q becomes “High”
(“1”). When the computer 3 reads the latch 5 to access the file, the output 13 of the address decoder 11 becomes "Low" and "1" is output to the computer 3 via the buffer 9. In this case, as shown in the flowchart of FIG. 4, the computer 3 operates to read the directory section of the disk. After the computer finishes reading the latch 5, the output of the address decoder 11 enters the reset input R of the RS-FF 8 via the delay circuit 14, and the output Q becomes Low ("0"). After this, if you read the latch 5 every time you access the file, the same operation as above will occur and "0" will be output to the computer 3, so you can access the file without reading the directory section of the disk. It can be done.

In the embodiment described above, the user presses the switch 6 each time a disk is replaced, but the switch 6 is linked to the door of the disk drive device, and when the door is closed, the switch 6 closes and the door is closed. It is clear that the same operation can be achieved even if the switch 6 is opened when the switch is opened.
That is, in Fig. 6, exactly the same operation can be realized by inputting the edge information when the door is opened and closed to replace the disk as the signal S indicated by the arrow in the figure to the switch information holding circuit 5. .
In this case, an effect can be obtained in that the user does not have to press the switch 6 each time.

Further, as another embodiment in which the switch 6 is opened and closed, a configuration as shown in FIG. 7, which detects whether or not a disk is loaded, is also possible. In FIG. 7, the hatched portion is a cross section showing the wall surface of the disk drive device 1. As shown in FIG. The switch 6 is spring-shaped and is open when no disk is loaded, as shown in (a), and closed when a disk is loaded, as shown in (b). In the case of this embodiment as well, the edge information when the switch 6 is opened or closed is sent to the signal S shown by the arrow in FIG.
If input into the switch information holding circuit 5 as
It is clear that the same operation as the embodiments of FIGS. 5 and 6 can be realized. In the case of the embodiment shown in FIG. 7 as well, the switch 6 is automatically closed when a disk is loaded (that is, when replaced), so the user does not have to press the switch every time the disk is loaded.

As described above, according to this embodiment, whether the disk 2 is newly loaded into the drive device 1 or
Check if it has been loaded before and has not been changed.
There is an effect that the computer 3 can be notified, and there is also an effect that this detection can be performed automatically.

〔Effect of the invention〕

According to the present invention, in a file information retrieval device using a file device such as a flexible disk device in which media on which information is recorded can be exchanged,
Either the media has been newly loaded or
Since it is possible to detect whether the media has been previously loaded (that is, the media has been previously accessed and the media itself has not been changed since then), the file management information is This has the effect of improving the efficiency of file searches.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of a magnetic disk, and Figure 2 is an illustration of a magnetic disk.
Figure 3 is an explanatory diagram of the internal directory section of the disk.
FIG. 4 is a block diagram for explaining the principle of the file information retrieval device according to the present invention. FIG. 4 is a flowchart showing the operating procedure of the control means. FIG. The figure is a timing chart of the main part of FIG. 5, and FIGS. 7a and 7b are explanatory diagrams of other embodiments of the present invention. 1...Flexible disk drive device, 2...
Flexible disk, 3... Computer main body, 4... Switch input circuit, 5... Switch input information holding circuit.

Claims (1)

[Scope of Claims] 1. Information reproducing means loaded with a recording medium in which file information and management information for managing the file information are recorded, and reproducing recorded information recorded on the loaded recording medium; A memory into which management information in recorded information outputted from the information reproducing means is written; and a file controlling the information reproducing means to reproduce file information determined by the management information read from the memory from a loaded recording medium. an access means; a holding means for selectively holding initial data and control data different from the initial data; an initialization means for setting initial data in the holding means; a setting means for setting control data in the holding means when management information of the recording medium is written to the memory; and a setting means for setting control data in the holding means when a file is accessed. If there is, the file access means is operated based on the management information already written in the memory, and if the initial data is held in the holding means, the management information of the recording medium loaded in the information reproducing means is written into the memory. , a control means for operating a file access means based on the written management information, and a file information retrieval device comprising: 2. The file information search device according to claim 1, wherein the initializing means includes a switch circuit that is opened and closed when the recording medium is attached or removed. 3. The file information search device according to claim 1, wherein the setting of the control data by the setting means is performed when the file access reads the data held in the holding means. 4. The file information search device according to claim 1, wherein the setting of the control data by the setting means is performed when management information is read from the recording medium. 5. The file information retrieval device according to any one of claims 1 to 4, wherein the initializing means, holding means, and setting means are integrated with the information reproducing means.