phil@amdcad.AMD.COM (Phil Ngai) (04/29/88)
I am interested in the subject of how one can use big disks on PC AT
clones. In particular there is the Seagate 4096, 80 megabyte, 28 ms,
available for $699. How will my computer handle it? Does the setup
command know about its drive type? What do programs like Disk Manager,
Golden Bow V/Feature, and Speed Stor do for me? Do I need a new BIOS
ROM chip(s)? Can I have partitions bigger than 32 Mb?
Normally I would read the manual but you can't seem to do that without
buying the product and it is amazing how expensive they are. Why
should a disk driver cost $99 when DOS is less than that? Why can't
Golden Bow put any kind of description on the package? Am I spoiled by
shareware?
I tried talking to the salesman but afterwards, I felt almost as
confused as I think he was.
--
Make Japan the 51st state!
I speak for myself, not the company.
Phil Ngai, {ucbvax,decwrl,allegra}!amdcad!phil or phil@amd.compete@octopus.UUCP (Pete Holzmann) (04/30/88)
In article <21346@amdcad.AMD.COM> phil@amdcad.AMD.COM (Phil Ngai) asks about
big drives, big partitions, and fancy disk manager programs.
I've been looking at all this a lot recently. Here's some answers:
[By the way... this article is Copyright 1988 by Octopus Enterprises. You
may use this information in any way that you like, as long as it doesn't
get republished without permission. I'm not charging you for the info, so
please don't charge others for it either!]
You CAN handle drives bigger than 32MB as long as you are using DOS 3.x
(earlier versions of DOS didn't have a big enough FAT table to make it
practical).
You CAN have partitions bigger than 32MB as long as you don't use some of
the low-level hard drive interface programs that assume a normal (2K) cluster
size. PC Tools, for example, gets sick on partitions bigger than about 160M.
The (amazing, wonderful, etc) new 'SpinRite' program that optimizes low-level
formats can't handle partitions >32MB in its current version. Norton seems
to be OK. CHKDSK can get sick.
What are the pieces of the puzzle?....
BIOS: Doesn't directly support drives >1024 cylinders, thus requiring special
device drivers. The 'Setup Drive Type' table imposes limitations on
wasted disk space vs. your boot partition (see below). The BIOS
generally doesn't care two hoots about partition size.
DOS: Except for custom versions (Toshiba and Compaq), no version of MSDOS
supports partitions bigger than 32MB. No (standard) version of DOS
prior to 3.3 directly supports multiple 32MB partitions on a single
drive.
CONTROLLER: # heads and # cylinders supported is limited by the controller.
Some controllers have special support for large drives. E.g. OMTI
and Adaptec have built-in low level formatting, and partitioning
into N 32MB partitions. OMTI makes itself look like lots of separate
drives. Adaptec loads a special driver into your boot partition; the
driver then takes care of telling DOS about the extra partitions.
SPECIAL DEVICE DRIVER/PARTITIONER: These things have several functions, some
of which could be accomplished in other ways, some of which need the
special software:
a) Low level format (usually doable using debug & controller firmware)
b) Override 'Setup drive type' table. (generally unique)
c) Fancy partitioning, e.g. >32MB partitions (generally unique)
d) High level format (also can be done using DOS FORMAT command)
e) Intense surface test of drive (also doable with other purchased
software)
What are the limitations? Let me outline them in some kind of category
sequence:
BUCKS:
In general, you'll end up spending a nice chunck of change ($50 or more) on
a 'disk partition manager' program in order to deal with big drives and/or
big partitions. Why so much bucks? Because the programs are necessary, they
are NOT a mass- market item, and they are easily pirated.
There are some exceptions:
a) If you just need to handle big drives, but don't need big partitions, you
have a few low cost choices:
1) Use DOS 3.3. It handles lots of 32MB partitions on a single drive.
Downside is that 3.3 is a memory hog (and typically costs
a little more than 3.2 anyway).
2) Use an RLL drive and an Adaptec RLL controller (e.g. 2372 HD/FD
controller). You pay maybe $70 extra for the controller, but
you get 50% more disk space, 400% more throughput (700K/sec),
and the controller firmware is able to download a FOO.SYS
partition manager driver onto your boot partition (nice trick!)
b) If you are buying a Seagate drive, the drive usually comes with a custom
version of Disk Manager included. First partition must be <=32MB,
but other partition(s) can be >32MB.
BIOS PROM LIMITATIONS:
If your BIOS doesn't have a drive table entry that supports a drive with
a) # Cylinders <= # Cylinders on your drive
b) # Heads <= # Heads on your drive
then you need a new BIOS. The problem is that the startup test will
crash and burn because it can't find the whole drive listed in your
setup parameters.
If your BIOS doesn't have a drive table entry that supports a drive with
a) # Cylinders <= # Cylinders on your drive
b) # Heads EQUAL TO # Heads on your drive (*note* above was <= )
then your boot partition is going to waste some potential disk space.
The boot partition can only use heads listed in the BIOS drive table.
For example, if your drive has 18 heads, your setup params drive has
4, and you make a 10 MB boot partition (C: drive), you'll have 10MB
of wasted space (heads 4-7 on the first cylinders of the drive).
GENERAL BIOS LIMITATION
If your drive has more than 1024 cylinders (e.g. Maxtor 1140, 2190, etc),
it gets very interesting. INT 13 in the BIOS does not support more than 1024
cylinders. So what to do?....
a) Use an OMTI RLL controller and SpeedStor
b) Buy your drive from Storage Dimensions (makers of SpeedStor and
a subsidiary of Maxtor); they'll give you a souped up version
of SpeedStor that handles >1024 cylinders on just about ANY
controller. [*flame*- is bundling like this legal? I thought
that bundled software also had to be made available separately
at a reasonable price!]
c) Buy the generic version of Disk Manager along with their 'SuperProm'
extended BIOS drive table [$100 for two PROMS. Yech.] [They
are working on a new version of Disk Manager that doesn't
need the extra PROMS. It'll be ready Real Soon Now].
d) Buy Vfeature Deluxe from Golden Bow ($110 or so)
BOOT PARTITION SIZE LIMITATIONS
Almost all known large-drive-handling methods require the boot partition to
be <=32MB. The exception is Vfeature Deluxe, which claims to allow the first
partition to be huge if you want. I've got a copy coming in early next week;
we'll see....
In addition, under many circumstances [seems somewhat random so far], many
disk-partition-managers/DOS versions/??? require the boot partition on a
large drive to be bigger than 16MB or you won't be able to boot from the
hard drive. Has something to do with FAT table sizes. Someday I may understand
this problem better, but for now suffice it to say that you may end up making
the boot partition bigger than you would otherwise like.
OTHER LIMITATIONS
The Seagate version of Disk Manager isn't flexible enough to work with most
RLL controllers. I've tried Adaptec and OMTI. Haven't tried Western Digital.
The problem is that most RLL controllers steal the last cylinder for their
own use, so a nominally 820 cylinder drive looks like it has 819. This drives
DM crazy.
OMTI controllers steal 1K at the end of your 640K (so you end up with 639K).
This makes EEMS backfill impossible on '286 machines. On '386 machines, if
you get "386 to the Max", they can send you a little routine that relocates
the stolen 1K to low memory so backfill will work properly.
RECOMMENDATIONS
IF you are getting a Seagate drive and normal controller, use the free DM.
IF you don't care about big partitions, use DOS 3.3 or an Adaptec controller
and spend the saved bucks on your sweetie.
IF you are getting an OMTI controller, get SpeedStor. They work well together.
IF you are getting a < 1024 cylinder drive, SpeedStor works and is cheap.
IF your boot partition must be big, or your drive is > 1024 cylinders, get
Vfeature Deluxe [tentative recommendation based on lengthy talk with
their tech support; I haven't tried it yet].
Tech support experience: GREAT: SpeedStore, Disk Manager, Golden Bow. OK:
[slow to answer, limited hours] Adaptec. NOT OK: [had to wait for
callback several times] OMTI.
--
OOO __| ___ Peter Holzmann, Octopus Enterprises
OOOOOOO___/ _______ USPS: 19611 La Mar Court, Cupertino, CA 95014
OOOOO \___/ UUCP: {hpda,pyramid}!octopus!pete
___| \_____ Phone: 408/996-7746ralf@B.GP.CS.CMU.EDU (Ralf Brown) (04/30/88)
In article <205@octopus.UUCP> pete@octopus.UUCP (Pete Holzmann) writes: }In addition, under many circumstances [seems somewhat random so far], many }disk-partition-managers/DOS versions/??? require the boot partition on a }large drive to be bigger than 16MB or you won't be able to boot from the }hard drive. Has something to do with FAT table sizes. Someday I may understand }this problem better, but for now suffice it to say that you may end up making }the boot partition bigger than you would otherwise like. The reason is that DOS FORMAT (and likely a lot of other programs) use 12-bit FATs for drives <16M, and 16-bit FATs for drives >16M. My 40M drive is split 30/10, and the 10M partition was using 4K clusters. I fairly recently reformatted it with 2K clusters, but to do so I had to a) patch the boot sector by hand to show 2K clusters (FORMAT used 4K) b) build the FATs and root directory by hand c) patch the device driver to not assume 4K clusters for partitions less than 16M The reason for the switchover at 16M is that 12-bit FATs can only have about 4080 clusters, which works out to just over 16M at 4K/cluster. }-- } OOO __| ___ Peter Holzmann, Octopus Enterprises } OOOOOOO___/ _______ USPS: 19611 La Mar Court, Cupertino, CA 95014 } OOOOO \___/ UUCP: {hpda,pyramid}!octopus!pete }___| \_____ Phone: 408/996-7746 -- {harvard,uunet,ucbvax}!b.gp.cs.cmu.edu!ralf -=-=- AT&T: (412)268-3053 (school) ARPA: RALF@B.GP.CS.CMU.EDU |"Tolerance means excusing the mistakes others make. FIDO: Ralf Brown at 129/31 | Tact means not noticing them." --Arthur Schnitzler BITnet: RALF%B.GP.CS.CMU.EDU@CMUCCVMA -=-=- DISCLAIMER? I claimed something?
eli@spdcc.COM (Steve Elias) (05/01/88)
Peter Holzmann posted a great summary of the big disk issue... here's two more cents... i just managed to get an 85M maxtor running on my clone, which has a phoenix bios. the bios supposedly supported this drive directly (as type 28). i set it up as 28, but when i started formatting with phoenix's format program -- it said there were only 768 cylinders... apparently the phoenix bios is a bit confused, or perhaps their formatting program... the solution was the OnTrack disk manager (not for resale!?). it allowed my to use 'type 15 -- the reserved disk type'... the disk manager writes the drive configuration directly onto the start of the disk -- i guess the bios is smart enough to look there for the heads/cylinders/precomp info... in any case, there may be some problems i haven't hit yet -- but the Disk Manager software was the key factor in getting this drive formatted. i used ibm at advanced diagnostics to do the lowlevel format after DM wrote the heads/cylinders/precomp info at the start of the disk.
keithe@tekgvs.TEK.COM (Keith Ericson) (05/01/88)
In article <21346@amdcad.AMD.COM> phil@amdcad.AMD.COM (Phil Ngai) writes: > >I am interested in the subject of how one can use big disks on PC AT >clones. In particular there is the Seagate 4096, 80 megabyte, 28 ms, >available for $699. How will my computer handle it? Does the setup >command know about its drive type? What do programs like Disk Manager, >Golden Bow V/Feature, and Speed Stor do for me? Do I need a new BIOS >ROM chip(s)? Can I have partitions bigger than 32 Mb? > Beginning with MS-DOS 3.3 (and I assume PC-DOS 3.3) you no longer need these adjunct disk driver routines if the disk you're adding is in the ROM BIOS disk table. Fdisk constructs one bootable, Normal DOS partition and one Extended DOS partion. The Extended DOS partition is then divided (by fdisk) into as many logical drives as you want. (My 284 Mbyte CDC Wren IV contains drives C: through K:. C: through J: are each 33+ Megabytes; K: is around 17 Megabytes.) If your drive is not in the table then you'll need one of the programs like Disk Manager (Ontrack), SpeedStore (?), or VFeature Deluxe (Golden Bow Systems). I know more about Disk Manager (DM) and VFeature Deluxe (VFD) than Speedstore. The worst problem is when there is no entry in the table that matches the number of heads in your disk. DM handles this by setting up a small C: partition - just large enough for the system files, config.sys, command.com, autoexec.bat, and the disk driver, dmdrvr.bin. VFD handles this case better and does not require using a partition for this. If there is an entry that matches the number of heads you're in better shape. Both DM and VFD are OK. Both VFD and SpeedStore have the capability of making your large disk into a single (large) partition. VFD can even span one partition over multiple disk drives. (Why?) VFD has this lousy copy protection, however, that I absolutely detest. I play around with far too many computers, drives, users, offices, locations, whatever, to be stuck with worrying about uninstalling some software before I take the machine apart. I've quit using - and recommending - VFD soley because of this difficulty. The copies of DM I've received have come with the drives - we buy almost exclusively from Eltech Research in Milpitas CA. They have always shipped DM with the 40-Megabyte-and-over drives. keith (more opinions available; I'm just too tired to keep typing) ericson
pete@octopus.UUCP (Pete Holzmann) (05/01/88)
In article <1570@pt.cs.cmu.edu> ralf@B.GP.CS.CMU.EDU (Ralf Brown) writes: }In article <205@octopus.UUCP> I write: }}[Boot partitions often have to be bigger than 16MB or you can't boot from }} the hard disk. Has to do with FAT table sizes, but why, I don't know]. }The reason is that DOS FORMAT (and likely a lot of other programs) use 12-bit }FATs for drives <16M, and 16-bit FATs for drives >16M. [explains the pain }of forcing small clusters/big FAT on partitions <16M] Thanks for filling out the FAT size explanation. Unfortunately, I still don't know why the 12 bit fat on small partitions disables booting off the disk! Does anybody know for sure? I could make a wild guess, which would be: DOS looks at the DRIVE size, sees that it is big, assumes a big FAT, then chokes on the small fat actually present in the boot partition. <<<That was a GUESS, not FACT>>>... obviously DOS is *able* to boot off of small- FAT drives, else you couldn't have a 10MB boot drive under current DOS versions... Does anybody know fer shure? Pete -- OOO __| ___ Peter Holzmann, Octopus Enterprises OOOOOOO___/ _______ USPS: 19611 La Mar Court, Cupertino, CA 95014 OOOOO \___/ UUCP: {hpda,pyramid}!octopus!pete ___| \_____ Phone: 408/996-7746
madd@bu-cs.BU.EDU (Jim Frost) (05/02/88)
In article <21346@amdcad.AMD.COM> phil@amdcad.AMD.COM (Phil Ngai) writes: |I am interested in the subject of how one can use big disks on PC AT |clones. In particular there is the Seagate 4096, 80 megabyte, 28 ms, |available for $699. How will my computer handle it? Does the setup |command know about its drive type? It may take some fiddling, but it will know about the drive type. When I was installing one in our true-blue, the docs said "use the type number on the disk" with a picture. Of course it wasn't purchased from IBM so there was no number. VFeature had a table of them, however, so we were in business. |What do programs like Disk Manager, |Golden Bow V/Feature, and Speed Stor do for me? Do I need a new BIOS |ROM chip(s)? Can I have partitions bigger than 32 Mb? I've only used VFeature, but what it lets you do is: * password protect your hard drive (if you like) * concatenate multiple disks into one logical volume (or break a large volume into smaller ones) * use disks larger than 32Mb (ours is 72Mb formatted) It comes with low-level formatter and a partitioner. The documentation for both wasn't very good, but I got by so you CAN pull the info out of it if you try. We did not require new ROMS. |Normally I would read the manual but you can't seem to do that without |buying the product and it is amazing how expensive they are. Why |should a disk driver cost $99 when DOS is less than that? When you need the driver, you need it bad. That's why we bought it. |I tried talking to the salesman but afterwards, I felt almost as |confused as I think he was. Well, if you have questions on VFeature, I'm a very satisfied user. Never found a bug in 3 years of heavy use on truly bizarre hardware. Be aware that many programs really don't like big volumes. We were unsuccessful in making Norton Utilities (whatever the version was before the Enhanced Version) run, and SoftLogic's disk optimizer barfed on the 2048-byte sectors. Aside from that everything has worked great. jim frost madd@bu-it.bu.edu
madd@bu-cs.BU.EDU (Jim Frost) (05/02/88)
In article <3402@tekgvs.TEK.COM> keithe@tekgvs.UUCP (Keith Ericson) writes: |Both VFD and SpeedStore have the capability of making your large disk into a |single (large) partition. VFD can even span one partition over multiple disk |drives. (Why?) Lots of reasons. From a hacker point of view, you have more read-write heads and can get better performance. This is usually moot because you only tend to combine smaller, slower drives into large partitions, not large fast ones. From a secretary point of view, you don't have to remember which disk whatever is on. Trust me, the concept of multiple hard disks is over the head of a good number of secretaries. Come to think of it, the concept of a wordprocessor is too. From a accountant's point of view, it can be cheaper to buy two dirt-cheap tiny drives and make them act like one expensive big one. This is becoming less of a motive as big drive prices hit rock bottom. |VFD has this lousy copy protection, however, that I absolutely detest. I |play around with far too many computers, drives, users, offices, |locations, whatever, to be stuck with worrying about uninstalling some |software before I take the machine apart. I've quit using - and |recommending - VFD soley because of this difficulty. This is true -- I'd forgotten. VFD makes you make "working disks". This has both good and bad points. Good point is it's a forced-backup. Bad point is it's a pain in the neck. It doesn't seem to care how many "working disks" you have, though, since I've made quite a few without complaints. The copy-protection is a minimal setback that I'd probably overlook only because you really don't have to use the disk very often, and the working disks are used, not the original. It's a pain to get started with the system, but smooth afterward. I abhor copy protection, but a protection method that requires you to backup your original in order to use it has at least some merit. jim frost madd@bu-it.bu.edu
pjh@mccc.UUCP (Pete Holsberg) (05/02/88)
Has anyone found that the controller has a big effect on HD performance. I have a Micropolis 1335 (71MB formatted, 28ms) drive with a DTC 5280 controller in a 386 box, and the Infoworld benchmark says that it is a dog! CORETEST 2.4 and PC Mag Benchmark suite 4 agree that it is a 28 ms drive! Steve Satchell (IW) has yet to answer this question about what the IW test does that might make this combo look so bad. Perhaps one of you has a thought?? Thanks.