Path: utzoo!mnetor!uunet!husc6!bbn!gatech!udel!mmdf
From: Leisner.Henr@xerox.com (marty)
Newsgroups: comp.os.minix
Subject: Re: Minix compatibility rumors
Message-ID: <1021@louie.udel.EDU>
Date: 20 Jan 88 15:22:57 GMT
Sender: mmdf@udel.EDU
Lines: 77

I have a hard disk driver which runs successfully on both 6 amd 8 Mhz PC ATs.
Does the official driver also run on 6 and 8 Mhz PCs?  I've seen various fixes
to the disk driver over time, but have pretty much ignored them since I'm
running on my ATs without problems and also some Wyse clones.

In the compatibility listing:
IBM PC-AT @6MHz	 	ast@cs.vu.nl		yes		yes
IBM PC-AT @8MHz	 	ast@cs.vu.nl		yes		no

Note it is a hacked (cleaner?) up V1.1 driver.  I read the Western Digital
specs, saw some things which didn't fully make sense and tried to get the drive
r
to agree to the spec.

What's the story on the 6 and 8 Mhz ATs? 

I currently am using the driver in both protected and real mode Minix systems. 
 
One of the things I did was changed the definitions:

#define WIN_REG1       0x1f0		/* data register */
#define WIN_REG2       0x1f1		/* error count   */
#define WIN_REG3       0x1f2		/* sector count  */
#define WIN_REG4       0x1f3		/* sector number */
#define WIN_REG5       0x1f4		/* cylinder number (low byte) */
#define WIN_REG6       0x1f5		/* cylinder number (high byte) */
#define WIN_REG7       0x1f6		/* sdh register		*/
#define WIN_REG8       0x1f7		/* status/command register */
#define WIN_REG9       0x3f6		/* alternate fixed disk status */

to

#define WIN_BASE_ADDR		0x1f0
#define WIN_DATA_REG		WIN_BASE_ADDR
#define WIN_ERROR_REG		WIN_BASE_ADDR + 1
#define WIN_SECTOR_COUNT	WIN_BASE_ADDR + 2
#define WIN_SECTOR_NUMBER	WIN_BASE_ADDR + 3
#define WIN_CYL_NUM_LOW		WIN_BASE_ADDR + 4
#define WIN_SDH_REG		WIN_BASE_ADDR + 6
#define WIN_STATUS_REG		WIN_BASE_ADDR + 7
#	define	STATUS_ERR	1
#	define	STATUS_IDX	2
#	define	STATUS_CRD	4
#	define  STATUS_DRQ	8
#	define	STATUS_SC	0x10
#	define  STATUS_WF	0x20
#	define 	STATUS_RDY	0x40
#	define	STATUS_BSY	0x80

#define WIN_FIXED_DISK		0x3f6
#	define RESET_CONTROLLER	0x4
#	define	WIN_INTR_ENABLE	0x2


This made it a little easier to work with the code and the data book at the sam
e
time.

I also use the Aztec port i/o functions (inportb, outportb).  Basically 
instead of inportb(foo, &result) I use

result = inportb(foo);

If there's interest, I could post the driver.  It would take a little work to
get it to run on a standard Minix system.

Something I never got around to do is change all "magic bits" being tested to
the above #defines.

 marty
ARPA:	leisner.henr@xerox.com
GV:  leisner.henr
NS:  martin leisner:henr801c:xerox



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