amdahl@homxc.UUCP (05/12/87)
I recently installed a segate 238 harddisk and RLL controller in my Xerox 6060 (a.k.a. att 6300). While the low level format program and the dos format both said the disk was 32MB (614 cyls,26sectors, 4hds). after setting up a partition to use the entire drive and formatting that, the chkdsk routine only found 21MB. I'm certain someone else on the net described an identical problem, however, i can't find it or the solution anywhere. If I remember correctly, it may have had something to do with the ROM bios. My machine has 1.36 . Do I need to upgrade to 1.43 or something in order to use the whole disk? thanks for any help, Paul Adams Amdahl Corp.
wtm@neoucom.UUCP (Bill Mayhew) (05/14/87)
Hi Net; I've answered this question to several people with Xerox 606x machines before, but the question keeps coming up. Xerox uses a menu driven program that is the logical equivalent of the more common MS-DOS FDISK for partitioning hard drives. The problem is that the Xerox HDMAINT, or whatever it's called, doesn't know about your RLL controller. It retrieves the number of heads on your drive and the number of tracks (4 heads, 633 tracks, I think for a Seagate ST-238) from the BIOS table on your HDU controller card. It then multiplies 633 tracks * 4 heads * 17 sectors = 21 meg. It then sets up the FAT on your drive to reflect this computation. Ah, there's the rub!-- 17 sectors. On RLL formatted drives, there are 26 sectors per track = 50% storage increase. There are several solutions, the least desirable of which is to let your machine go on thinking you only have 20 meg. You can edit the FAT manually with DEBUG, but this is tedious and requires an IBM or AT&T DOS technical reference manual. You could also use the Norton Utilities, version 4.0, which makes the procedure somewhat easier. I'd rate this approach as not too practical. You can buy Speedstor, cost ~$90 (ugh!) which can handle virtually any drive/controller combination. It will do a nice job. This is an expensive, but effective solution. You can buy AT&T DOS 3.1, release 1.01 or later and use AT&T's FDISK program to set up the partition table on your drive. AT&T's program is smart enough to look at your RLL controller and realize that your drive has 26 sectors per track. There are several brain-damaged areas in Xerox DOS 3.1, thus having AT&T DOS is desirable any way. Xerox DOS is better in one respect, though; their GWBASIC handles CGA mode graphics correctly. There are a couple of bugs in AT&T's GWBASIC CGA graphics. So get AT&T DOS 3.1, but hang on to your Xerox GWBASIC. --Bill Bill Mayhew Dvision of Basic Medical Sciences Northeastern Ohio Universities' College of Medicine Rootstown, OH 42272 USA phone: 216-325-2511 (wtm@neoucom.UUCP ...!cbatt!neoucom!wtm)