I don't see how switching from a 1010 to a 2010 will help with the number of
heads in a controller => drive interface. Both chips have three bits to
define the head address. One thing that could be done with the external SDH
register, however, is encode a drive select bit as a head address. However,
the hardware to do that would already have to be in place. Most controllers
did it the long slow way, using an external device to generate the head and
drive select signals. I used several different drives with more than eight
heads, using the drive select in at least one case. It's merely a matter of
lying to the device with its bit defiitions. However, the track and sector
ID fields will have a seemingly wrong head address if the fact that a
mapping trick is in place isn't taken into account in the formatting
routine. Any checks of the contents of the head field in the SDH register
will reflect what the chip knows is the correct number of heads as it has
read it from the drive's sector ID field, and the driver software has to
compensate for that. If you're in a position to use that signal as a
partitioning vehicle, you're that much ahead of the game. The user and the
OS will understand much more easily if a physical drive change occurs when a
drive change is signalled in the SDH address.
Dick
----- Original Message -----
From: Neil Cherry <ncherry_at_home.net>
To: <classiccmp_at_classiccmp.org>
Sent: Saturday, October 28, 2000 9:58 PM
Subject: Re: AT&T 7300
> The 7300/3B1 was capable of running SYSV R3.1, I had a 3B1 with 3.2
> because I worked at the hotline. I was never able to get the ethernet
> board so I resorted to Starlan. I still have 1 7300 and an RS232 NAU.
>
> My 3B1 first died in 88, the power supply went. I build a board to convert
> a PC power supply to the 3B1 power supply connector. I also added an AC
> fan to keep it cool and quiet. I still have the tape drive and probably
> the RS232 ports and 8088 board for it. I also have the software.
>
> I seemed to recal being able to reset all the passwords via the menu
> system so as long as you could get in you could reset all the passwords.
>
> Oh, I also still have the 8 head mods to the hard drive system. You would
> swap in a 2010 for the WD1010 and solder on this mod to get the extra
head.
> Unfortunately the 3B1 went out the door when the drive died (80M, $939 to
> replace). I then started with Linux on a 386SX/16. I still have that one
> but the keyboard controller is fried but Linux still runs.
>
> --
> Linux Home Automation Neil Cherry ncherry_at_home.net
> http://members.home.net/ncherry (Text only)
> http://meltingpot.fortunecity.com/lightsey/52 (Graphics)
> http://linuxha.sourceforge.net/ (SourceForge)
>
>
Received on Sat Oct 28 2000 - 23:35:57 BST