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- INTRCPT.DOC - Version 3
- May 5, 1986
-
- Intercept is a memory resident program which monitors interrupts 40H and
- 2FH << Function 17, operation 35 >>. Basically, what this program does
- is allows AT users with a high capacity drive in position A to format,
- read, and write 720K disks using the cheaper low density diskettes. This
- way you can double the storage without spending an arm or a leg for the
- higher priced ultra density diskettes and achieve compatibility with other
- MS DOS systems using quad density drives! Since the high capacity drives
- really are 96TPI, FM and MFM, this program along with DRIVER.SYS opens
- up a new storage method.
-
- To use this program, you first must be running under DOS 3.2 or greater,
- be running with an AT, have DRIVER.SYS installed as a device driver in
- your CONFIG.SYS file, and have a HIGH CAPACITY drive in drive position
- A. Your config.sys entry must be as follows:
- DEVICE=DRIVER.SYS /D:0
- When the system boots, it will tell you what the NEW drive letter is,
- remember it since you must enter it in the command line when calling
- INTRCPT. In my system which I used to write this program, I have two
- high capacity drives, 2 hard disks, and a RAM disk; therefore, my new
- drive became F. In my AUTOEXEC.BAT file, I have an entry as follows:
- INTRCPT F
- This entry in the command line is extremely important because it tells
- the software which drive specifier to monitor.
-
- Two interrupts are monitored: 40H and 2FH. The 40H interrupt is the BIOS
- interrupt which handles the floppy disks and the 2F interrupt is the
- MULTIPLEXER interrupt which allows me to monitor the drive specifier.
- Since the function that I am intercepting is "INTERNAL TO DOS", a
- considerable amount of time was spent trying to verify that I wouldn't
- cause any problems with other functions.
-
- The following files are included in this archive:
- 1) INTRCPT.DOC This file
- 2) INTRCPT.COM The load module
- 3) INTRCPTX.ASM The SOURCE ASSEMBLY file
- 4) INTRCPT.CON An example of the entry in CONFIG.SYS
- 5) INTRCPT.BAT An example of the entry in AUTOEXEC.BAT
-
-
- THIS SOFTWARE IS PLACED IN THE PUBLIC DOMAIN for your use and UNDER NO
- conditions may a fee be charged for it. The ARCHIVE file MUST be
- distributed in its complete form.
-
- This software is given "AS IS" without any guarantees. The user takes
- full responsibility. Under NO conditions will I take the liability for
- any damages caused by its usage.
-
- Sanford J. Zelkovitz
- Alpha Computer Service
- 5300 Orange Ave. Suite 108
- Cypress, CA 90630
- Voice: 714-828-0286 << 82-80286 >>
- Data: 714-898-8634
-
-
- Additions to version 3:
-
- DISKCOPY and DISKCOMP NOW work with the software. Also, INT 21H - function
- 44H - subfunction D is monitored to allow DISKCOPY & DISKCOMP to operate.
-
- A VERIFY command is performed whenever the IOCTL interrupt in intercepted.
- This may cause an unexpected read to be performed; however, this is normal
- and is necessay.