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Text File
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1986-07-22
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3KB
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63 lines
This is an attempt to try to show how the Home Compute
Magazine article dated September 1984 allows the PCjr to add
a second disk drive. The article is very complete and to the
point but a few minor changes have been added that seem to
help in my case at least.The two chips that are added as
piggybacks are 74LS10 and 74LS175. If you use an open
collector like the 7412 (not 74LS12) it seems to handle a lot
of different drives including both half heights and full
heights. Everything else is identical to the original
article.
I talked to some one that said the drive addition did
not allow the use of the IBM memory expansion and ramdisk
files.I will try to show how it was done on my machine which
works with 640 k and usually a 360k ram when uploading files.
It also works with the SASI interface and a hard disk as
well.
The original article said to make an autoexec.bat file
which I was able to modify slightly to allow the use of the
IBM memory expansion files. Following is the example that I
use:
AUTOEXEC.BAT :
IF EXIST switch.bat GOTO first
GOTO last
:first
RENAME switch.bat off.bat
RENAME c.fig config.sys
BOOT
:last
RENAME off.bat switch.bat
RENAME config.sys c.fig
DATE
TIME
(REST OF THINGS YOU WANT)
C.FIG IS REALLY MY CONFIG.SYS FILE WITH EVERYTHING IN IT LIKE
EXAMPLE BELOW:
C.FIG:
DEVICE=PCJRMEM.COM
DEVICE=RAMDISK.COM /360
DEVICE=ANSI.SYS
The only other thing was the listing of the modboot.bat file
that had to be modifided.
MODBOOT.BAT:
A 0:9080
XOR AX,AX
MOV DS,AX
OR BY [410],40
NOP
G=0:9080 9089
L 0:7C00 0 0 1
G=0:7C00
I hope this clears up a few of the problems that had to
be overcome by my close associates and me. The drive works
marvelous and and as to date has not had any hangups that can
be related to the software boot. Hope this has not violated
any laws or such but hope it helps some out there as it is a
joy to use now. If you want to drop a note or write me please
do so ..BERT STARK 9323 WICKERSHAM SAN ANTONIO TX 78250 TEL#
1-512-6805867