Path: utzoo!utgpu!water!watmath!looking!brad
From: brad@looking.UUCP (Brad Templeton)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Bios upgrade for old AT
Keywords: Low-down underhanded IBM ploy
Message-ID: <1475@looking.UUCP>
Date: 13 Mar 88 03:19:04 GMT
References: <3903@batcomputer.tn.cornell.edu> <182@tscs.UUCP>
Reply-To: brad@looking.UUCP (Brad Templeton)
Organization: Looking Glass Software Ltd.
Lines: 60


I just did some work on that 40 meg miniscribe on my old AT.  The only
thing you need that's tough is to get a low level format done on the whole
drive.  You need a low level format program (like SpeedStore and others)
that can format a drive that isn't in the list of official ones.

The dealer who sold you the drive should format it for you.  It's the
simplest way.

Anyway, with this done, the neat thing is that, once under Dos 3.3, fdisk
is the only program that looks at the cylinder number.  So, use this little
TSR provided below to temporarily change the drive descriptor to the
808 cylinders of the miniscribe (I hear some can do as many as 840, mind you)
and then use fdisk (dos 3.3) to create an extra dos partition beyond the
32 megs.  After that, the drive will still work, even set as a 32 meg
drive type code "3".

Here's the TSR.  It's really boring, and you don't need it all the time.

PROGRAM	SEGMENT	PARA	PUBLIC 'CODE'
	ASSUME 	cs:PROGRAM

TBSR	PROC

	; set up our table

	mov	al,41h		; int number for disk table
	mov	ah,37		; dos function to set vector
	push	cs
	pop	ds		; put code segment into ds
	mov	dx,offset drive + 100h
	int	21h

	; now terminate, but stay resident

	mov	dx,(lastloc-TBSR+15+256) / 16
	mov	ah,49		; TSR
	mov	al,0
	int	21h		; terminate program

drive	dw	808		; number of cylinders
	db	6		; heads
	dw	0
	dw	300		; write pre-comp
	db	0
	db	0		; control byte
	db	0,0,0		; dunno
	dw	808		; landing zone
	db	17		; sectors
	db	0


lastloc	LABEL	NEAR

TBSR	ENDP

PROGRAM	ENDS
	END
-- 
Brad Templeton, Looking Glass Software Ltd. - Waterloo, Ontario 519/884-7473