CN1081525A - Hard disk write-proof interface device - Google Patents

Abstract

A write-resistant interface device for hard disk comprises a decoding circuit and a path control circuit, so that the hard disk of PC has the function of preventing data from being written. The decoding circuit is used to decode the signals related to the write data of hard disk outputted by data bus and address bus of personal computer, and a signal output end controls the action of path control circuit, and the path control circuit can generate the action of allowing personal computer to write or inhibiting write data into hard disk according to the signal.

Description

The present invention relates to an anti-write device for a data storage body, in particular to an anti-write circuit configuration for a hard disk, so that the hard disk drive used in a personal computer has the function of preventing data from being written.

General personal computers, such as IBM compatible personal computers, are all equipped with two kinds of disk devices for storing data, one is a floppy disk, and the other is a hard disk. For the use of the floppy disk drive, the data is read through a disk (such as a 51/4″ floppy disk). If the disk needs to be protected from writing, it is only necessary to use a sticker to cover the write-proof gap of the disk. , to prevent intentional or unintentional writing. But for the use of hard disks, there is no similar write-proof function, so users cannot do easy write-proof like using floppy disks.

In order to solve the above problems, some commercially available software is provided to the user in a software control mode to prevent writing of the hard disk, but when performing this function, the software must be loaded into the main memory of the personal computer, and the software must be executed, or The software is permanently stored in the main memory in the form of a permanent program. Obviously, this prior art cannot avoid occupying the limited memory of the computer mainframe and the time of the central processing unit. Therefore, this technology also has its disadvantages.

The main purpose of the present invention is to provide a hard disk write protection device, which can prevent the hard disk used in personal computers from being affected by unintentional or intentional data writing, so as to ensure the data security of the hard disk.

Another object of the present invention is to provide an easy-to-use hard disk write-protection interface device, which has a selection function for the user to choose whether to need the write-protection function or not. When the setting state is not anti-write, the use of its hard disk is exactly the same as that of the general hard disk, and when the setting state of anti-write is selected, the anti-write interface of the present invention will automatically detect the personal computer address bus and data The specific command signal sent by the bus bar activates the anti-write function.

Other objectives and circuit design of the present invention will be described in detail below, and further understanding of the present invention will be obtained with reference to the accompanying drawings.

Wherein Fig. 1 is the circuit configuration diagram of the present invention.

As shown in Figure 1, the anti-write interface device of the present invention mainly comprises a decoding circuit 1 and a path control circuit 2, and the input terminal of decoding circuit 1 is used for being connected to the relevant data in the data bus of personal computer and address bus. Lines and address lines, the associated data lines are SD0-SD7, and the associated address lines are SA0-SA9. The decoding circuit 1 has an output terminal CON, which is used as an anti-write control line. The anti-write control signal is used to control the operation status of the path control circuit 2, and the path control circuit 2 performs anti-write or non-write protection according to the anti-write control signal. transmission of signals.

In the decoding circuit 1, four NOT gates I1, I2, I3, I4, six OR gates R1-R6 and two NAND gates N1, N2 are included. Among them, the input terminal of the NAND gate I1 is used to connect to the address line SA3 of the personal computer, and its output is connected to one of the input terminals of the NAND gate N1, and the other input terminals of the NAND gate N1 are connected to SA0, SA1, SA2, SA4 , SA5, SA6 and SA8. After this circuit configuration, the signal of hexadecimal 1F7 or 177 generated by the address bus can be deciphered, which is the hard disk read and write command issued by the personal computer.

In terms of data bus, the signals related to data writing are 50, 30, 31, 32, and 33 in hexadecimal, where signal 50 represents formatting instructions, and 30, 31, 32, and 33 represent writing Instructions, the decoding device of the present invention must also decode these signals. The circuit configuration of NOT gate I2, I3 and OR gate R1, R2 among Fig. 1 is to understand the write instruction of 30, 31, 32, 33, and the signal that solves is sent into the input end of OR gate R5; Instead of gate I4, or gate R3, R4 can solve the signal of hexadecimal 50, and send this representative formatting command to the input end of or gate R6. The output ends of the OR gates R5 and R6 are respectively connected to the input ends of the NAND gate N2. Therefore, when the decoding circuit 1 interprets the status of the data written in the hard disk, the output terminal CON of the NAND gate N2 can control the anti-write The signal is sent out to control the action of the path control circuit 2.

The input terminal of the path control circuit 2 is to receive the data writing control line IOW in the personal computer bus. In the path control circuit 2, there is a write-protection setting switch SW1, and the user can select different setting positions according to needs. When the user switches to position B, the non-write-proof path is selected, so the signal of the data writing control line 1OW is directly sent to the hard disk interface; and when the user switches to position A, the signal of the data writing control line 1OW is then Controlled by the three-state buffer I5, that is, when the output terminal CON of the decoding circuit is at a high potential, the data writing control line IOW is connected to the hard disk interface through the three-state buffer I5 and the setting switch SW1; otherwise, when the decoding circuit When the output terminal CON is at a low potential, the data writing control line IOW will not be able to reach the hard disk interface, thereby preventing the hard disk from being written into data.

Claims (1)

1. A kind of rigid disk writing-proof interface device, be with the data write activity of interface arrangement control PC to rigid disk, it is characterized in that, this interface arrangement comprises a decoding circuit and a path control circuit, the input end of described decoding circuit is used to be connected to the data bus-bar and the address bus-bar of PC, to separate the disk read-write instruction of reading address hygiene stream row, and in separating the format command signal 50 of reading sexadecimal 1F7/177 signal and data bus and writing instruction 30,31,32,33 o'clock, send one by the output terminal of this decoding circuit and control signal to described path control circuit, the data that the input end of this path control circuit is used to be connected to PC write control line, its output terminal is then as the write control signal of hard disk, allows to write or suppresses to write the action of data to rigid disk thereby the path control circuit is carried out according to the output signal of decoding circuit.

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