kahn@cs.odu.edu (Gary I Kahn) (05/08/89)
Has anyone out there ever used an XT compatible harddisk controller in an AT clone? Is there a way to make it bootable? I don't know anything about AT setup programs. The controller in question is an Adaptec RLL controller. I tried writing the company, but they ignored my letter. Please respond by mail. I'll post a summary. Thanks in advance. Gary I. Kahn kahn@odu.edu A A
hollen@eta.megatek.uucp (Dion Hollenbeck) (05/09/89)
Sorry to have to post this to the net, the @$%&$*@Q% mailer bounced it on me three times, an anyway, it may be useful to other people also. kahn@cs.odu.edu (Gary I Kahn): > Has anyone out there ever used an XT compatible harddisk controller in an > AT clone? Is there a way to make it bootable? I don't know anything about > AT setup programs. The controller in question is an Adaptec RLL controller. > I tried writing the company, but they ignored my letter. Please respond > by mail. I'll post a summary. Thanks in advance. > I am using an OMTI controller from Scientific Microsystems. I had it in my XT when I upgraded to a baby AT motherboard. I needed to tell the BIOS via the SETUP program that there were NO harddisks in the system. This allowed the BIOS on the hard disk controller card to be used instead of in the ROM. In the process of booting, the BIOS checks at every 16k boundry from segment 0C000h on up and if it finds an identifying byte at offset 0 (I think), it knows that there is a ROM there with code to be executed. This code in in the standard format of a DOS installable device driver, so the BIOS merely calls indirectly the init code in the ROM from the address stored in the ROM at a known offset. The BIOS in the hard disk controller card then takes over the hard disk interrupt vector which was already loaded by the ROM BIOS and now there is magically a hard disk in the system. I have a friend who has an Adaptec controller from a XT in an AT and he has no trouble booting it, so I think this will work for you. Dion Hollenbeck (619) 455-5590 x2814 Megatek Corporation, 9645 Scranton Road, San Diego, CA 92121 seismo!s3sun!megatek!hollen ames!scubed/