25 May
2007
25 May
'07
2:37 p.m.
The standard floppy controller can drive up to four floppies, two
internal and two external. And the motherboards of these machines
have dip switches that allow you to tell them how many drives are
connected. But those switches are just a simple count of drives, not
which chain the drives are connected to.
Normally I see these machines with two internal floppies, and nothing
else. On the 5160 I have here in the office I am about to add an
external floppy using the external connector on the floppy controller;
the machine has a single drive installed internally now. How does the
BIOS handle this situation? If I tell it that there are 2 drives will
it try to figure out that one is internal and one is external? Do I
need device driver help, or is this something the BIOS tries to
handle? Is there something on the controller card I am supposed to do
to tell it how the drives are connected/organized?
Mike
25 May
25 May
3:31 p.m.
On 25 May 2007 at 7:37, mbbrutman-cctalk at brutman.com wrote:
Normally I see these machines with two internal
floppies, and nothing
else. On the 5160 I have here in the office I am about to add an
external floppy using the external connector on the floppy controller;
the machine has a single drive installed internally now. How does the
BIOS handle this situation? If I tell it that there are 2 drives will
it try to figure out that one is internal and one is external? Do I
need device driver help, or is this something the BIOS tries to
handle? Is there something on the controller card I am supposed to do
to tell it how the drives are connected/organized?
No, the 5150 is somewhat simple-minded when it comes to floppies.
There's nothing in the BIOS RAM area that identifies the exact
position of drives installed. If you have only a single internal
drive installed and one external drive, the BIOS will expect that
you've specified 3 drives and you will receive a non-fatal error 601
(IIRC) when it comes to look for drive B:.
If you're running a version of DOS later than about 3.2, you can get
around this problem by setting the mobo switches to the number of
internal drives you have, then use DRIVER.SYS to specify the external
drives.
A similar situation obtains for hard disks on the XT--the controller
expects that you will have a drive 0 installed if you have a drive 1
installed--even though electrically, there's no requirement for it--
only that there should be proper termination on whatever the last
drive on the cable is.
Cheers,
Chuck
7:04 p.m.
On Fri, 25 May 2007 mbbrutman-cctalk at brutman.com wrote:
The standard floppy controller can drive up to four
floppies, two
internal and two external. And the motherboards of these machines
have dip switches that allow you to tell them how many drives are
connected. But those switches are just a simple count of drives, not
which chain the drives are connected to.
Normally I see these machines with two internal floppies, and nothing
else. On the 5160 I have here in the office I am about to add an
external floppy using the external connector on the floppy controller;
the machine has a single drive installed internally now. How does the
BIOS handle this situation?
simplisticly
If I tell it that there are 2 drives will
it try to figure out that one is internal and one is external?
NO
Do I need device driver help,
NO
or is this something the BIOS tries to handle?
NO
Is there something on the controller card I am
supposed to do
to tell it how the drives are connected/organized?
NO
You have two choices.
You can set the switches for three drives (two internal, one external).
That will work fine, but, ...
every time that you try to access drive B:, you will get a "drive not
ready"
You will lose out on the "phantom" B: drive that you have with only one
floppy. ("COPY A:x B:x" prompts, "put the B: disk in the drive";
"put the
A: disk in the drive", etc.)
Your external drive will be C:, and your hard drive will be D: . That is
how it is supposed to work, but much BRAIN-DEAD software is hardwired for
C:. For example, to install MS-DOS 6.00, Microsoft says to install it on
C: (your external floppy!), and then copy it to the hard disk !
or,
you can set the switches for 1 drive, and run DOS 3.20 or higher, with
"DEVICE = DRIVER.SYS /D:2" You will have A:, a phantom B:, your hard
drive will be C:, and the external drive will be handled by a device
driver, and be D: .
Optionally, you can include a /F:x or /T:x/N:y to let DOS know which kind
of drive it is (NO, you can not use arbitray values of x and y for oddball
drives (/T:35))
You can change boot disks, without messing with switches when you
connect/disconnect/change the external floppy.
With EITHER method, if you access your external floppy through BIOS
(INT13h), instead of through DOS, it will be drive #2
(internal floppies are #0, #1, external are #2, #3; hard drives are #80h,
#81h)
--
Grumpy Ol' Fred cisin at xenosoft.com
11:18 p.m.
The standard floppy controller can drive up to four floppies, two
internal and two external. And the motherboards of these machines
have dip switches that allow you to tell them how many drives are
connected. But those switches are just a simple count of drives, not
which chain the drives are connected to.
Normally I see these machines with two internal floppies, and nothing
else. On the 5160 I have here in the office I am about to add an
external floppy using the external connector on the floppy controller;
the machine has a single drive installed internally now. How does the
BIOS handle this situation? If I tell it that there are 2 drives will
it try to figure out that one is internal and one is external? Do I
need device driver help, or is this something the BIOS tries to
handle? Is there something on the controller card I am supposed to do
to tell it how the drives are connected/organized?
The BIAS is, as usual, brain-dead. It assumes you'll fit both internal
drives before adding external ones. So if you set it for 2 or more drives
and only have one intenral drive, it'll give an error at boot-up
Moreover, if you have 3 or 4 drives, they will be asseigned the letters
A: B: C; (and D:) by MS-DOS, putting the first hard disk partition at E:.
A _very_ large number of installation programs get confused by this.
My suggestion is to set the DIP switches to say you have one floppy
drive. And then (asuming you're running a late-enough MS-DOS) to use
DRIVER.SYS to operate the external drives. If you do that, the internal
drive will be A: _and B: (as it would be on a single-drive machine), your
hard dirve partitions will start at C:, and your exernal drive(s) will
have letters assigned after the last hard drive partition.
-tony
26 May
26 May
3:07 a.m.
New subject: Punch card file drawers.
A while back, Someone here was looking for punch card file cabnets and there was several
metos'.
I have located 3 Standard 4 foot, 10highx2wide file cabinets. 2 Gray and one Orange/Red.
They are here in Columbus Ohio. I will be looking into shipping options next week for
those
who are interested.
I have seen the packing and shipping subject raised here numerious times in the past, and
am open to current comments and suggestions.
I will take my portable scale over next week and get their measurements and a weight.
Over the next few months I will be assisting in shutting down and parting out
a small Data Services Company here in Columbus.
A complete running and I believe still on maint-contract.
IBM 4331-2 cpu with
3803 with 4 3420 tape drives
3830 with 8 3350 disk drives
and just about every document ever produced for or about this system.
There is an IBM Powerserver 370 with CD, DAT tape, and front loading 9 track, and monitor,
with a lot of doc and a a stack of CD's including a bunch of AIX disks.
There is a large Tartan Pluss data entry controller with several racks of Z80 single board
computers each with an RS232 port on each with about 8 data entry keypunch stations.
There are two complete systems here one running live and the other is a running backup.
Any interested parties feel free to contact me directly, I have a few pictures on my phone
from todays quick walk through and will get more next
week when I get a chance to inventory
things in more detail.
The system is not due to be powered down until later in July, But the much of the other
Stuff
can and will go on eBay over the next few weeks as it is photoed, written up, and pugged
into
Auction Wizard.
The other stuff includes but is not limited to:
A complete working 129 80col punch that looks to be in very good condition.
A small amount of System360 and unit record documentation, including a desk top burster,
and rig to remove the carbon from 2 part forms and a bunch of other
"stuff"....
To those of us here in the good old USA, have a happy, long weekend !
Bob Bradlee.
Bob at Bradlee.org
3:09 a.m.
And that is how it wound up. I left the dip switches on the motherboard
set to one drive and used DRIVER.SYS to create a drive letter for the
external drive.
For some strange reason, the IBM 4865 external drive unit that I am
using showed up as drive number 3, not 2. (Counting from zero, of
course.) I wonder if there is a twist in the internal cabling, or the
drive select jumper is non-standard on this one. No problem it works
just fine.
The XT in general is a beautiful machine:
512K
Original 10MB hard disk
Original IBM Monochrome/Printer adapter and 5151 Monochrome monitor
VGA card, driving a flat panel display that it shares
3COM 3C503
One internal floppy (full height), one IBM 4865 external floppy
Parallel port Zip disk
I've got this sitting where I work (Big Blue) next to my regular systems
in my office. You'd be surprised at how many people don't recognize
what it is, or how old it is.
Mike
Tony Duell wrote:
The BIAS is, as usual, brain-dead. It assumes
you'll fit both internal
drives before adding external ones. So if you set it for 2 or more drives
and only have one intenral drive, it'll give an error at boot-up
Moreover, if you have 3 or 4 drives, they will be asseigned the letters
A: B: C; (and D:) by MS-DOS, putting the first hard disk partition at E:.
A _very_ large number of installation programs get confused by this.
My suggestion is to set the DIP switches to say you have one floppy
drive. And then (asuming you're running a late-enough MS-DOS) to use
DRIVER.SYS to operate the external drives. If you do that, the internal
drive will be A: _and B: (as it would be on a single-drive machine), your
hard dirve partitions will start at C:, and your exernal drive(s) will
have letters assigned after the last hard drive partition.
-tony
2:40 a.m.
On Fri, 25 May 2007, Michael B. Brutman wrote:
For some strange reason, the IBM 4865 external drive
unit that I am
using showed up as drive number 3, not 2. (Counting from zero, of
course.) I wonder if there is a twist in the internal cabling, or the
drive select jumper is non-standard on this one. No problem it works
just fine.
a LACK OF A TWIST will do that
5:37 p.m.
I understand that the nickname is 'Grumpy Old Fred', but it is necessary
to YELL because I got the existence/non-existence of the twist in the
cable backwards?
If I had said that the cause of the drive ID weirdness was because I
have my US electrical socket installed with the grounding pin facing
downward then I could understand the caps lock for emphasis, but in the
grand scheme of things that was really a minor nit.
Fred Cisin wrote:
On Fri, 25 May 2007, Michael B. Brutman wrote:
For some strange reason, the IBM 4865 external
drive unit that I am
using showed up as drive number 3, not 2. (Counting from zero, of
course.) I wonder if there is a twist in the internal cabling, or the
drive select jumper is non-standard on this one. No problem it works
just fine.
a LACK OF A TWIST will do that
8:54 p.m.
On Sat, 26 May 2007, Michael B. Brutman wrote:
I understand that the nickname is 'Grumpy Old
Fred', but it is necessary
to YELL because I got the existence/non-existence of the twist in the
cable backwards?
Sorry
my emphasis was not intended to offend you
If I had said that the cause of the drive ID weirdness
was because I
have my US electrical socket installed with the grounding pin facing
downward then I could understand the caps lock for emphasis, but in the
grand scheme of things that was really a minor nit.
a number of years ago, I saw why some insist on putting the ground prong
up. A colleague was measuring the room (for new equipment), using a tape
measure. The tape slid down the wall, and right into the tiny gap between
a plug and its socket
--
Grumpy Ol' Fred cisin at xenosoft.com
6427
days inactive
6428
days old
8 comments
5 participants
participants (5)
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ard＠p850ug1.demon.co.uk -
caveguy＠sbcglobal.net -
cclist＠sydex.com -
cisin＠xenosoft.com -
mbbrutman-cctalk＠brutman.com