john@minster.york.ac.uk (07/13/89)
Has anyone out there tried a MiniScribe 8450 40Mb hard card with Minix on an IBM-PC/XT? Let me tell you a tale of woe. A couple of months ago I bought an 8450 for my XT, used its built-in low-level formatter, and recompiled Minix 1.2 on floppy to incorporate xt_wini.c. (I had the disk on approval, just in case the drive's controller was incompatible with both drivers). It worked first time. (I then had to recompile fs and fsck to alter the no. of sectors/track from 17 to 26, and to increase NR_BUF_HASH in fs/const.h to permit 4 file systems to be mounted simultaneously). I used the 1.2 fdisk to make three partitions (20Mb, 5Mb and 15Mb - but see later), then mkfs to make the file systems. I used diskcheck from 1.3 to show that the disk was ok but for the blocks of two tracks I had marked bad during low-level format (from the manufacturer's defect list). These I isolated with the 1.3 version of badblocks. Two or three hours later I got an "unrecoverable disk error" for a hard disk block. I ran diskcheck and fsck - no error was found. In the next week similar errors occurred every two or three hours of computing. Some of the errors smashed directories - and finally my /usr/lib/src directory was smashed - I used fsck to repair the filesystem. I backed up my files and bought a copy of Paul Mace software's Htest/Hformat (see Jerry Pournelle's column in the June '89 Byte). I ran Htest (under MS-DOS, of course) in R/W mode for several days and nights. Apart from the locked out tracks, the only error it detected was when it caused the heads to seek to track `-1'. Is my disk defective, or is there a deficiency in the 1.2 xt_wini.c? Actually, the 1.2 mkfs would only let me have a 7Mb third partition (20Mb + 5Mb + 7Mb = 32Mb). The 32Mb size in mkfs seems to be a per-file-system limit, so surely that's not this problem. Next, I used Hformat and xfdisk from the same suite to re-establish my three partitions. Mkfs gave the same problem. Diskcheck showed no unexpected errors, but when I tried an experimental compilation of the 1.3 mkfs I received an "unrecoverable disk error" within five minutes of using Minix. Although I have 1.3, I doubt I'd get very far building it on hard disk - and doing the build on floppy would be a pain. Can any expert out there advise me how to proceed? I'm tempted to write off the MiniScribe, and buy a new hard disk (>= 40Mb). Can any UK Minix users who have retro-fitted a hard drive to an XT recommend a model and a supplier? --------------------------------------------------------------------------- John A. Murdie UK 0904 432752 Dept. of Comp. Sci. seismo!mcvax!ukc!minster!john University of York England