jwbirdsa@amc-gw.amc.com (James Birdsall) (10/02/90)
I just ran into an interesting problem with an RLL drive.
I have a Toshiba MK134 and a Western Digital RLL controller (8-bit, I
forgot to look at the model the last time I had the computer open). The
Toshiba is ~65M and has 7 heads. When the RLL 26 sectors/track are remapped
to 17 sectors/track, the number of cylinders is still under the BIOS limit
of 1024.
I just tried to install a Mitsubishi MR535. It is the same size but only
has 5 heads, so the number of remapped cylinders is well over 1024, making
about 22M inaccessible.
I tried Disk Manager (came with the drive) as a last ditch; it tried to
tell the controller BIOS to not remap the drive, but returned with the
message "THE CONTROLLER BIOS DOES NOT SUPPORT NONSTANDARD CONFIGURATIONS."
So, even through I'm running the drive RLL, I'm only getting ~44M (which
is the MFM rating!). And Disk Manager (which I don't want to run but I want
the extra space more) can't help with my present controller.
So, can somebody point me at an 8-bit RLL controller that CAN handle
nonstandard configurations?
Thanks in advance.
--
---
James W. Birdsall jwbirdsa@amc.com 71261.1731@compuserve.com
Compu$erve: 71261,1731 GEnie: J.BIRDSALL2
For it is the doom of men that they forget. -- MerlinRFM@psuvm.psu.edu (10/02/90)
Five heads??? Seven heads???? I always thought heads can in EVEN multiples. Maybe you're confused because the first head is numbered zero. Try 6 or 8, as the case may be.
chao@oahu.cs.ucla.edu (Chia-Chi Chao) (10/02/90)
In article <90274.223047RFM@psuvm.psu.edu> RFM@psuvm.psu.edu writes: >Five heads??? Seven heads???? I always thought heads can in EVEN multiples. >Maybe you're confused because the first head is numbered zero. Try 6 or >8, as the case may be. Voice coil driven drives usually have _ODD_ number of usable heads, as one is used by the drive itself to detect where the tracks are. -- Chia-Chi Chao chao@cs.ucla.edu ..!ucbvax!cs.ucla.edu!chao
kdq@demott.COM (Kevin D. Quitt) (10/02/90)
In article <90274.223047RFM@psuvm.psu.edu> RFM@psuvm.psu.edu writes: >Five heads??? Seven heads???? I always thought heads can in EVEN multiples. >Maybe you're confused because the first head is numbered zero. Try 6 or >8, as the case may be. Lots of disks have an odd number of heads for data, because one head is used for sync tracks on a separate platter. Use of this technique lets the disk write denser data because it can compensate for the variations in the speed of the platters. -- _ Kevin D. Quitt demott!kdq kdq@demott.com DeMott Electronics Co. 14707 Keswick St. Van Nuys, CA 91405-1266 VOICE (818) 988-4975 FAX (818) 997-1190 MODEM (818) 997-4496 PEP last 96.37% of all statistics are made up.
poffen@sj.ate.slb.com (Russell Poffenberger) (10/03/90)
In article <90274.223047RFM@psuvm.psu.edu> RFM@psuvm.psu.edu writes: >Five heads??? Seven heads???? I always thought heads can in EVEN multiples. >Maybe you're confused because the first head is numbered zero. Try 6 or >8, as the case may be. Sure heads may be odd numbers. Many modern drives dedicate one head (surface) for servo feedback positioning info, and is unavailable to the user. Russ Poffenberger DOMAIN: poffen@sj.ate.slb.com Schlumberger Technologies UUCP: {uunet,decwrl,amdahl}!sjsca4!poffen 1601 Technology Drive CIS: 72401,276 San Jose, Ca. 95110 (408)437-5254
rfutscher@pbs.org (10/04/90)
In article <90274.223047RFM@psuvm.psu.edu>, <RFM@psuvm.psu.edu> writes: > Five heads??? Seven heads???? I always thought heads can in EVEN multiples. > Maybe you're confused because the first head is numbered zero. Try 6 or > 8, as the case may be. One head is used as a servo head. This leaves an odd number of heads for data.
davidsen@sixhub.UUCP (Wm E. Davidsen Jr) (10/07/90)
In article <631@demott.COM> kdq@demott.COM (Kevin D. Quitt) writes: | Lots of disks have an odd number of heads for data, True. | because one head | is used for sync tracks on a separate platter. Often true. Some drives just don't have a head on the bottom or top platter for marketing or total height reasons. Marketing=enough bad platters on one side to make it worth useing them. No longer common, I admit. | Use of this technique | lets the disk write denser data because it can compensate for the | variations in the speed of the platters. Not usually the case. For voice coil positioning the platter with the sync track is used to position the head radially (to the correct track), and this allows more tracks per inch rather than more fcpi (bytes per track). -- bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen) sysop *IX BBS and Public Access UNIX moderator of comp.binaries.ibm.pc and 80386 mailing list "Stupidity, like virtue, is its own reward" -me