Hardware flakiness (Windoze BSOD)

[David Nebenzahl]

So I made up a SCSI cable for the scanner I got off the street
(literally), an Agfa SnapScan 1236. (Had to cobble up the cable since my
SCSI host adapter has a high-density socket but the scanner has the old
25-pin socket.) The cable's a bit ugly, with something of a rat's nest
of wires soldered together in the middle, but it works. Scanner works fine.

But since using the scanner, I've found that sometimes--not always--the
scanner seems to be causing a hardware fault that causes Windows blue
screens. Sometimes I can boot up and do dozens of scans; other times the
BSOD appears some time after booting, or when I access the scanner driver.

At first I wasn't sure whether the blue screens were due to the scanner
itself or the scanner driver, but I'm pretty sure it's the former, as I
never get them when I unplug the scanner.

I'm sure part of the problem can be traced to Windows 2000's rather
piss-poor SCSI handling. While it is definitely better than Windows NT,
which *really* sucked in that way, it's still problematic.

And the fact that I don't have a terminator on the scanner might not be
helping, either. But as I said, when it works I can do many scans with
no problems.

I should say that this isn't a critical problem for me. I have another
scanner that works about as well (a Microtek using USB) that works about
as well; the Agfa just happens to be a bit faster and not as annoyingly
noisy. I'm mainly curious why I'm having these problems.

Any guesses? (Educated ones get more points.)

Oh, almost forgot:

o OS: Windows 2000, SP 2
o Advansys SCSI host adapter ("fast/wide"), but I'm using regular old
single-ended SCSI II. The Advansys is basically a clone of the old
Adaptec 1542, but with two adapters (16 SCSI IDs) on one card. There are
two CD-ROM drives (Plextor) on the same bus as the scanner.
o Motherboard is an Asus something-or-other, almost 10 years old


--
Who needs a junta or a dictatorship when you have a Congress
blowing Wall Street, using the media as a condom?

- harvested from Usenet

 

[PeterD]

On Tue, 03 Nov 2009 00:27:20 -0800, David Nebenzahl
<nobody@but.us.chickens> wrote:

So I made up a SCSI cable for the scanner I got off the street
(literally), an Agfa SnapScan 1236. (Had to cobble up the cable since my
SCSI host adapter has a high-density socket but the scanner has the old
25-pin socket.) The cable's a bit ugly, with something of a rat's nest
of wires soldered together in the middle, but it works. Scanner works fine.

But since using the scanner, I've found that sometimes--not always--the
scanner seems to be causing a hardware fault that causes Windows blue
screens. Sometimes I can boot up and do dozens of scans; other times the
BSOD appears some time after booting, or when I access the scanner driver.

At first I wasn't sure whether the blue screens were due to the scanner
itself or the scanner driver, but I'm pretty sure it's the former, as I
never get them when I unplug the scanner.

I'm sure part of the problem can be traced to Windows 2000's rather
piss-poor SCSI handling. While it is definitely better than Windows NT,
which *really* sucked in that way, it's still problematic.

And the fact that I don't have a terminator on the scanner might not be
helping, either. But as I said, when it works I can do many scans with
no problems.

I should say that this isn't a critical problem for me. I have another
scanner that works about as well (a Microtek using USB) that works about
as well; the Agfa just happens to be a bit faster and not as annoyingly
noisy. I'm mainly curious why I'm having these problems.

Any guesses? (Educated ones get more points.)

Oh, almost forgot:

o OS: Windows 2000, SP 2
o Advansys SCSI host adapter ("fast/wide"), but I'm using regular old
single-ended SCSI II. The Advansys is basically a clone of the old
Adaptec 1542, but with two adapters (16 SCSI IDs) on one card. There are
two CD-ROM drives (Plextor) on the same bus as the scanner.
o Motherboard is an Asus something-or-other, almost 10 years old

1. You should repost in one of the SCSI forums/groups. Try
'comp.periphs.scsi' for a starting point.

2. Can the home-made cable. These are available commercially and are
wired properly and will work correctly. SCSI is not the place to
cobble a cable together, it is just too sensitive.

3. No terminator? Crap, no wonder it doesn't work. You need to learn
the rules for SCSI and follow them exactly.

4. Win 2K does fine with SCSI. It is your cables, card or device.

That this thing works at all is amazing.

 

[Meat Plow]

On Tue, 03 Nov 2009 00:27:20 -0800, David Nebenzahl
<nobody@but.us.chickens>wrote:

So I made up a SCSI cable for the scanner I got off the street
(literally), an Agfa SnapScan 1236. (Had to cobble up the cable since my
SCSI host adapter has a high-density socket but the scanner has the old
25-pin socket.) The cable's a bit ugly, with something of a rat's nest
of wires soldered together in the middle, but it works. Scanner works fine.

But since using the scanner, I've found that sometimes--not always--the
scanner seems to be causing a hardware fault that causes Windows blue
screens. Sometimes I can boot up and do dozens of scans; other times the
BSOD appears some time after booting, or when I access the scanner driver.

At first I wasn't sure whether the blue screens were due to the scanner
itself or the scanner driver, but I'm pretty sure it's the former, as I
never get them when I unplug the scanner.

I'm sure part of the problem can be traced to Windows 2000's rather
piss-poor SCSI handling. While it is definitely better than Windows NT,
which *really* sucked in that way, it's still problematic.

And the fact that I don't have a terminator on the scanner might not be
helping, either. But as I said, when it works I can do many scans with
no problems.

I should say that this isn't a critical problem for me. I have another
scanner that works about as well (a Microtek using USB) that works about
as well; the Agfa just happens to be a bit faster and not as annoyingly
noisy. I'm mainly curious why I'm having these problems.

Any guesses? (Educated ones get more points.)

Oh, almost forgot:

o OS: Windows 2000, SP 2
o Advansys SCSI host adapter ("fast/wide"), but I'm using regular old
single-ended SCSI II. The Advansys is basically a clone of the old
Adaptec 1542, but with two adapters (16 SCSI IDs) on one card. There are
two CD-ROM drives (Plextor) on the same bus as the scanner.
o Motherboard is an Asus something-or-other, almost 10 years old

What's the hex number reported on the blue screen. And terminate the
chain. Lots of bsods are driver oriented IRQ_DOES_NOT_EQUAL stuff
accompanied by a hex cod and the culprit modules.

 

[William Sommerwerck]

I used to run SCSI under W2K, using an Adaptec card, on an ASUS P4T board.
Never had any problems.

If you want to buy the cable I had made for my scanner (it's a long custom
model made by a Redmond cable company), let me know.

 

[D Yuniskis]

David Nebenzahl wrote:

So I made up a SCSI cable for the scanner I got off the street

(sigh) SayNoMore. SCSI cables need to have controlled impedances.
Even at ASYNC speeds, you can get all sorts of reflections that
can cause havoc.

(literally), an Agfa SnapScan 1236. (Had to cobble up the cable since my
SCSI host adapter has a high-density socket but the scanner has the old
25-pin socket.) The cable's a bit ugly, with something of a rat's nest
of wires soldered together in the middle, but it works. Scanner works fine.

And you know it works at DC, right. How do you know it works
"at speed"?

But since using the scanner, I've found that sometimes--not always--the
scanner seems to be causing a hardware fault that causes Windows blue
screens. Sometimes I can boot up and do dozens of scans; other times the
BSOD appears some time after booting, or when I access the scanner driver.

At first I wasn't sure whether the blue screens were due to the scanner
itself or the scanner driver, but I'm pretty sure it's the former, as I
never get them when I unplug the scanner.

I'm sure part of the problem can be traced to Windows 2000's rather
piss-poor SCSI handling. While it is definitely better than Windows NT,
which *really* sucked in that way, it's still problematic.

I have *7* SCSI busses in my W2K box. I don't see SCSI errors
*or* hangs. I'm currently running W2KS SP4 but have run W2K SP4
in the past with comparable performance.

And the fact that I don't have a terminator on the scanner might not be
helping, either. But as I said, when it works I can do many scans with
no problems.

Yeah, and if you have sex without a condom your lady friend probably
*won't* get pregnant -- MOST of the time. :-/

Do you put 66MHz memory on your 133MHz bus?
Do you run with your 5V power supply at 4.4V?
Do you overclock your CPU?

(sigh) If you want things to work as they are designed to work,
then *use* them as they were designed to be used!

SCSI cables can be incredibly finicky. The Standard even describes
*where* certain signals should be located *within* the cable
itself for optimum performance. I don't think this is a case
of picking nits just because there was nothing on TV that
afternoon... (i.e., if they went to this length to codify the
standard's requirements, there is a bonfide reason for doing so!)

I should say that this isn't a critical problem for me. I have another
scanner that works about as well (a Microtek using USB) that works about
as well; the Agfa just happens to be a bit faster and not as annoyingly
noisy. I'm mainly curious why I'm having these problems.

Any guesses? (Educated ones get more points.)

Oh, almost forgot:

o OS: Windows 2000, SP 2

Upgrade to SP4. While you can still find it on MS's website.

o Advansys SCSI host adapter ("fast/wide"), but I'm using regular old
single-ended SCSI II. The Advansys is basically a clone of the old
Adaptec 1542, but with two adapters (16 SCSI IDs) on one card. There are
two CD-ROM drives (Plextor) on the same bus as the scanner.

If there are "BIOS settings" (like the 1542's SCSIselect)
try setting the adapter to run ALL targets in ASYNC mode.
But, fix the cable and terminator!

o Motherboard is an Asus something-or-other, almost 10 years old

Look for bad caps.

 

[David Nebenzahl]

On 11/3/2009 6:02 AM Meat Plow spake thus:

What's the hex number reported on the blue screen. And terminate the
chain. Lots of bsods are driver oriented IRQ_DOES_NOT_EQUAL stuff
accompanied by a hex cod and the culprit modules.

Dunno the hex code (maybe I'll write it down next time it happens), but
you nailed the error message. Actually, I think the last time it was
something like IRQ_LESS_OR EQUAL, but in any case an IRQ level error.

To answer some replies upstream, I don't give enough of a shit about
this to invest anything in a good cable, but thanks for offering. I went
for the zero-cost solution, and like I said, it works most of the time.
Last night I scanned more than a dozen photos w/no problems.


--
Who needs a junta or a dictatorship when you have a Congress
blowing Wall Street, using the media as a condom?

- harvested from Usenet

 

[David Nebenzahl]

On 11/3/2009 8:43 AM D Yuniskis spake thus:

David Nebenzahl wrote:

So I made up a SCSI cable for the scanner I got off the street

(sigh) SayNoMore. SCSI cables need to have controlled impedances.
Even at ASYNC speeds, you can get all sorts of reflections that
can cause havoc.

Yes, I know all that. I simply wanted to see how far I could tempt the
angry SCSI gods.

(literally), an Agfa SnapScan 1236. (Had to cobble up the cable since my
SCSI host adapter has a high-density socket but the scanner has the old
25-pin socket.) The cable's a bit ugly, with something of a rat's nest
of wires soldered together in the middle, but it works. Scanner works fine.

And you know it works at DC, right. How do you know it works
"at speed"?

If you read my post again, you'll see that I've been successful using
this cobbled-together cable. Last night I scanned more than a dozen
photos with no problems. So I know it works "at speed". (Most of the
time, anyhow, with this device.)

The BSOD problem only rears its ugly head occasionally. I know how to
solve it (unplug the damn offending cable). I'm simply curious as to why
this happens. (Makes this kind of an N. Cook postmortem analysis.)


--
Who needs a junta or a dictatorship when you have a Congress
blowing Wall Street, using the media as a condom?

- harvested from Usenet

 

[Baron]

Meat Plow wrote:

On Tue, 03 Nov 2009 00:27:20 -0800, David Nebenzahl
nobody@but.us.chickens>wrote:

So I made up a SCSI cable for the scanner I got off the street
(literally), an Agfa SnapScan 1236. (Had to cobble up the cable since
my SCSI host adapter has a high-density socket but the scanner has the
old 25-pin socket.) The cable's a bit ugly, with something of a rat's
nest of wires soldered together in the middle, but it works. Scanner
works fine.

But since using the scanner, I've found that sometimes--not
always--the scanner seems to be causing a hardware fault that causes
Windows blue screens. Sometimes I can boot up and do dozens of scans;
other times the BSOD appears some time after booting, or when I access
the scanner driver.

At first I wasn't sure whether the blue screens were due to the
scanner itself or the scanner driver, but I'm pretty sure it's the
former, as I never get them when I unplug the scanner.

I'm sure part of the problem can be traced to Windows 2000's rather
piss-poor SCSI handling. While it is definitely better than Windows
NT, which *really* sucked in that way, it's still problematic.

And the fact that I don't have a terminator on the scanner might not
be helping, either. But as I said, when it works I can do many scans
with no problems.

I should say that this isn't a critical problem for me. I have another
scanner that works about as well (a Microtek using USB) that works
about as well; the Agfa just happens to be a bit faster and not as
annoyingly noisy. I'm mainly curious why I'm having these problems.

Any guesses? (Educated ones get more points.)

Oh, almost forgot:

o OS: Windows 2000, SP 2
o Advansys SCSI host adapter ("fast/wide"), but I'm using regular old
single-ended SCSI II. The Advansys is basically a clone of the old
Adaptec 1542, but with two adapters (16 SCSI IDs) on one card. There
are two CD-ROM drives (Plextor) on the same bus as the scanner.
o Motherboard is an Asus something-or-other, almost 10 years old

What's the hex number reported on the blue screen. And terminate the
chain. Lots of bsods are driver oriented IRQ_DOES_NOT_EQUAL stuff
accompanied by a hex cod and the culprit modules.

Isn't the Snapscan internally terminated ? ie only has a single 25 pin
data socket.

--
Best Regards:
Baron.

 

[David Nebenzahl]

On 11/3/2009 2:20 PM Baron spake thus:

On Tue, 03 Nov 2009 00:27:20 -0800, David Nebenzahl
nobody@but.us.chickens>wrote:

And the fact that I don't have a terminator on the scanner might
not be helping, either. But as I said, when it works I can do
many scans with no problems.

Isn't the Snapscan internally terminated ? ie only has a single 25 pin
data socket.

Nope; it has 2 sockets, and no termination switches that I can see, so
I'm ASSuming it's unterminated. (Most SCSI devices like this have two
sockets for daisy-chaining.)


--
Who needs a junta or a dictatorship when you have a Congress
blowing Wall Street, using the media as a condom?

- harvested from Usenet

 

[Warren Block]

David Nebenzahl <nobody@but.us.chickens> wrote:

On 11/3/2009 2:20 PM Baron spake thus:

On Tue, 03 Nov 2009 00:27:20 -0800, David Nebenzahl
nobody@but.us.chickens>wrote:

And the fact that I don't have a terminator on the scanner might
not be helping, either. But as I said, when it works I can do
many scans with no problems.

Isn't the Snapscan internally terminated ? ie only has a single 25 pin
data socket.

Nope; it has 2 sockets, and no termination switches that I can see, so
I'm ASSuming it's unterminated. (Most SCSI devices like this have two
sockets for daisy-chaining.)

With the cable as short as possible and no other devices, that can work
acceptably (FSVO "acceptably"). Anything more than a terminated
controller at the other end and all bets are off. Add a terminator,
preferably active, and it might even be trustworthy.

--
Warren Block * Rapid City, South Dakota * USA

 

[David Nebenzahl]

On 11/3/2009 5:12 PM Warren Block spake thus:

David Nebenzahl <nobody@but.us.chickens> wrote:

On 11/3/2009 2:20 PM Baron spake thus:

On Tue, 03 Nov 2009 00:27:20 -0800, David Nebenzahl
nobody@but.us.chickens>wrote:

And the fact that I don't have a terminator on the scanner might
not be helping, either. But as I said, when it works I can do
many scans with no problems.

Isn't the Snapscan internally terminated ? ie only has a single 25 pin
data socket.

Nope; it has 2 sockets, and no termination switches that I can see, so
I'm ASSuming it's unterminated. (Most SCSI devices like this have two
sockets for daisy-chaining.)

With the cable as short as possible and no other devices, that can work
acceptably (FSVO "acceptably"). Anything more than a terminated
controller at the other end and all bets are off. Add a terminator,
preferably active, and it might even be trustworthy.

Yes. Pretty sure the Advansys is auto-terminating.

The thing I was *really* hoping to discover--and it may be my fault for
not having been more clear in my original message--is why the Blue
Screen of Death, even assuming some sort of SCSI error due to my
cobbled-up cable? I mean, shouldn't the OS be able to handle a SCSI
error without abandoning ship? That's what I meant by "piss-poor SCSI
handing". I can't imagine, for example, that a Sun workstation would be
brought to its knees by a bad SCSI cable.

I'm just wondering what's going on there in driver-land, or HAL-land, or
wherever the problem may be.


--
Who needs a junta or a dictatorship when you have a Congress
blowing Wall Street, using the media as a condom?

- harvested from Usenet

 

[D Yuniskis]

David Nebenzahl wrote:

On 11/3/2009 5:12 PM Warren Block spake thus:

David Nebenzahl <nobody@but.us.chickens> wrote:

On 11/3/2009 2:20 PM Baron spake thus:

On Tue, 03 Nov 2009 00:27:20 -0800, David Nebenzahl
nobody@but.us.chickens>wrote:

And the fact that I don't have a terminator on the scanner might
not be helping, either. But as I said, when it works I can do
many scans with no problems.

Isn't the Snapscan internally terminated ? ie only has a single 25 pin
data socket.

Nope; it has 2 sockets, and no termination switches that I can see,
so I'm ASSuming it's unterminated. (Most SCSI devices like this have
two sockets for daisy-chaining.)

With the cable as short as possible and no other devices, that can
work acceptably (FSVO "acceptably"). Anything more than a terminated
controller at the other end and all bets are off. Add a terminator,
preferably active, and it might even be trustworthy.

Yes. Pretty sure the Advansys is auto-terminating.

The thing I was *really* hoping to discover--and it may be my fault for
not having been more clear in my original message--is why the Blue
Screen of Death, even assuming some sort of SCSI error due to my
cobbled-up cable? I mean, shouldn't the OS be able to handle a SCSI
error without abandoning ship? That's what I meant by "piss-poor SCSI
handing". I can't imagine, for example, that a Sun workstation would be
brought to its knees by a bad SCSI cable.

I'm just wondering what's going on there in driver-land, or HAL-land, or
wherever the problem may be.

You're assuming a driver will behave when the hardware doesn't.
If the hardware tugs on the IRQ line at 50KHz, what should the
driver do? Should it be encumbered with enough smarts to
*measure* that rate and "diagnose" the problem? Or, should it
just "/* CAN'T HAPPEN */" and crash?

Tie the IRQ from your IDE drive to a 50KHz signal and see how
*it* responds. You can do the same in a Sun box and see how
it (mis)behaves.

I wouldn't be expecting hardened drivers in an OS (like Windows)
that freely allows third parties to write drivers, design hardware,
etc.

 

[Bob Larter]

PeterD wrote:

On Tue, 03 Nov 2009 00:27:20 -0800, David Nebenzahl
nobody@but.us.chickens> wrote:

So I made up a SCSI cable for the scanner I got off the street
(literally), an Agfa SnapScan 1236. (Had to cobble up the cable since my
SCSI host adapter has a high-density socket but the scanner has the old
25-pin socket.) The cable's a bit ugly, with something of a rat's nest
of wires soldered together in the middle, but it works. Scanner works fine.

But since using the scanner, I've found that sometimes--not always--the
scanner seems to be causing a hardware fault that causes Windows blue
screens. Sometimes I can boot up and do dozens of scans; other times the
BSOD appears some time after booting, or when I access the scanner driver.

At first I wasn't sure whether the blue screens were due to the scanner
itself or the scanner driver, but I'm pretty sure it's the former, as I
never get them when I unplug the scanner.

I'm sure part of the problem can be traced to Windows 2000's rather
piss-poor SCSI handling. While it is definitely better than Windows NT,
which *really* sucked in that way, it's still problematic.

And the fact that I don't have a terminator on the scanner might not be
helping, either. But as I said, when it works I can do many scans with
no problems.

I should say that this isn't a critical problem for me. I have another
scanner that works about as well (a Microtek using USB) that works about
as well; the Agfa just happens to be a bit faster and not as annoyingly
noisy. I'm mainly curious why I'm having these problems.

Any guesses? (Educated ones get more points.)

Oh, almost forgot:

o OS: Windows 2000, SP 2
o Advansys SCSI host adapter ("fast/wide"), but I'm using regular old
single-ended SCSI II. The Advansys is basically a clone of the old
Adaptec 1542, but with two adapters (16 SCSI IDs) on one card. There are
two CD-ROM drives (Plextor) on the same bus as the scanner.
o Motherboard is an Asus something-or-other, almost 10 years old


1. You should repost in one of the SCSI forums/groups. Try
'comp.periphs.scsi' for a starting point.

2. Can the home-made cable. These are available commercially and are
wired properly and will work correctly. SCSI is not the place to
cobble a cable together, it is just too sensitive.

3. No terminator? Crap, no wonder it doesn't work. You need to learn
the rules for SCSI and follow them exactly.

4. Win 2K does fine with SCSI. It is your cables, card or device.

That this thing works at all is amazing.

Agreed, on all the above. The OP needs a commercial cable, & should
enable the terminator on one of the drives & put it on the end of the
cable. He should also make sure that termination is disabled on the
scanner & the other drive.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

 

[Bob Larter]

David Nebenzahl wrote:

On 11/3/2009 2:20 PM Baron spake thus:

On Tue, 03 Nov 2009 00:27:20 -0800, David Nebenzahl
nobody@but.us.chickens>wrote:

And the fact that I don't have a terminator on the scanner might
not be helping, either. But as I said, when it works I can do
many scans with no problems.

Isn't the Snapscan internally terminated ? ie only has a single 25 pin
data socket.

Nope; it has 2 sockets, and no termination switches that I can see, so
I'm ASSuming it's unterminated. (Most SCSI devices like this have two
sockets for daisy-chaining.)

Which device is one the end of the cable? Whichever it is, it needs to
be terminated, & *every* other device *must* be unterminated. If you
fail to do that, you will get unreliable operation. (If you've done all
that, the traditional trouble-shooting technique is to sacrifice a goat
to the SCSI gods. ;^)

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

 

[Bob Larter]

David Nebenzahl wrote:

On 11/3/2009 8:43 AM D Yuniskis spake thus:

David Nebenzahl wrote:

So I made up a SCSI cable for the scanner I got off the street

(sigh) SayNoMore. SCSI cables need to have controlled impedances.
Even at ASYNC speeds, you can get all sorts of reflections that
can cause havoc.

Yes, I know all that. I simply wanted to see how far I could tempt the
angry SCSI gods.

The SCSI gods are touchy, & quick to anger.

And you know it works at DC, right. How do you know it works
"at speed"?

If you read my post again, you'll see that I've been successful using
this cobbled-together cable. Last night I scanned more than a dozen
photos with no problems. So I know it works "at speed". (Most of the
time, anyhow, with this device.)

The BSOD problem only rears its ugly head occasionally. I know how to
solve it (unplug the damn offending cable). I'm simply curious as to why
this happens.

Simple: You're getting noise on your handshaking lines that's hammering
the SCSI I/F, then the OS, which then pukes on it's shoes. Fix the
termination & the problem should go away.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

 

[isw]

In article <hcpm6p$ofd$1@aioe.org>,
D Yuniskis <not.going.to.be@seen.com> wrote:

David Nebenzahl wrote:
So I made up a SCSI cable for the scanner I got off the street

(sigh) SayNoMore. SCSI cables need to have controlled impedances.
Even at ASYNC speeds, you can get all sorts of reflections that
can cause havoc.

Not always. I've seen (and owned) a number of SCSI peripherals hooked to
older Macs with no terminators and no problems. Strings up to three or
four units long, hot switching power to devices as needed, no problems.
Period.

In one case, I had such a setup that worked perfectly for years under OS
9, but failed totally when I migrated to OS X; fixed it by adding a
terminator, but I believe the problem was still software (SCSI timing
was faster with OS X and the lack of terminator became an issue solely
because reflections didn't have time to die out).

I'd guess that if a particular setup works most of the time, the problem
is more likely to be software than hardware. Check for better drivers.

Isaac

 

[D Yuniskis]

isw wrote:

In article <hcpm6p$ofd$1@aioe.org>,
D Yuniskis <not.going.to.be@seen.com> wrote:

David Nebenzahl wrote:
So I made up a SCSI cable for the scanner I got off the street
(sigh) SayNoMore. SCSI cables need to have controlled impedances.
Even at ASYNC speeds, you can get all sorts of reflections that
can cause havoc.

Not always. I've seen (and owned) a number of SCSI peripherals hooked to
older Macs with no terminators and no problems. Strings up to three or

How old were the Macs? Were they using (ancient) 5380 SCSI HBA's?

four units long, hot switching power to devices as needed, no problems.
Period.

In one case, I had such a setup that worked perfectly for years under OS
9, but failed totally when I migrated to OS X; fixed it by adding a
terminator, but I believe the problem was still software (SCSI timing
was faster with OS X and the lack of terminator became an issue solely
because reflections didn't have time to die out).

I'd guess that if a particular setup works most of the time, the problem
is more likely to be software than hardware. Check for better drivers.

 

[Meat Plow]

On Tue, 03 Nov 2009 11:09:25 -0800, David Nebenzahl
<nobody@but.us.chickens>wrote:

On 11/3/2009 6:02 AM Meat Plow spake thus:

What's the hex number reported on the blue screen. And terminate the
chain. Lots of bsods are driver oriented IRQ_DOES_NOT_EQUAL stuff
accompanied by a hex cod and the culprit modules.

Dunno the hex code (maybe I'll write it down next time it happens), but
you nailed the error message. Actually, I think the last time it was
something like IRQ_LESS_OR EQUAL, but in any case an IRQ level error.

To answer some replies upstream, I don't give enough of a shit about
this to invest anything in a good cable, but thanks for offering. I went
for the zero-cost solution, and like I said, it works most of the time.
Last night I scanned more than a dozen photos w/no problems.

My first Windows machines were NT3.5/NT4 servers and workstations and
used SCSI peripherals. I dealt for several years with SCSI chains,
RAID controllers up to 20 individual discs in Sun servers. Then came
faster IDE drives running in UDMA5 and now UDMA6 SATA/II.
So I have an extensive background adminstrating equipment that at the
time was only available with SCSI disks, tape, etc....

Your LESS_OR_EQUAL and depending on the hex string is more likely a
driver stomping on memory space allocated by another program/driver
running in the background.

 

[Meat Plow]

On Tue, 03 Nov 2009 22:20:47 +0000, Baron
<baron.nospam@linuxmaniac.nospam.net>wrote:

Meat Plow wrote:

On Tue, 03 Nov 2009 00:27:20 -0800, David Nebenzahl
nobody@but.us.chickens>wrote:

So I made up a SCSI cable for the scanner I got off the street
(literally), an Agfa SnapScan 1236. (Had to cobble up the cable since
my SCSI host adapter has a high-density socket but the scanner has the
old 25-pin socket.) The cable's a bit ugly, with something of a rat's
nest of wires soldered together in the middle, but it works. Scanner
works fine.

But since using the scanner, I've found that sometimes--not
always--the scanner seems to be causing a hardware fault that causes
Windows blue screens. Sometimes I can boot up and do dozens of scans;
other times the BSOD appears some time after booting, or when I access
the scanner driver.

At first I wasn't sure whether the blue screens were due to the
scanner itself or the scanner driver, but I'm pretty sure it's the
former, as I never get them when I unplug the scanner.

I'm sure part of the problem can be traced to Windows 2000's rather
piss-poor SCSI handling. While it is definitely better than Windows
NT, which *really* sucked in that way, it's still problematic.

And the fact that I don't have a terminator on the scanner might not
be helping, either. But as I said, when it works I can do many scans
with no problems.

I should say that this isn't a critical problem for me. I have another
scanner that works about as well (a Microtek using USB) that works
about as well; the Agfa just happens to be a bit faster and not as
annoyingly noisy. I'm mainly curious why I'm having these problems.

Any guesses? (Educated ones get more points.)

Oh, almost forgot:

o OS: Windows 2000, SP 2
o Advansys SCSI host adapter ("fast/wide"), but I'm using regular old
single-ended SCSI II. The Advansys is basically a clone of the old
Adaptec 1542, but with two adapters (16 SCSI IDs) on one card. There
are two CD-ROM drives (Plextor) on the same bus as the scanner.
o Motherboard is an Asus something-or-other, almost 10 years old

What's the hex number reported on the blue screen. And terminate the
chain. Lots of bsods are driver oriented IRQ_DOES_NOT_EQUAL stuff
accompanied by a hex cod and the culprit modules.

Isn't the Snapscan internally terminated ? ie only has a single 25 pin
data socket.

Don't know. Most of the scanners I've owned had a chain port where a
terminator would be installed if its the last device.

 

[baron]

David Nebenzahl Inscribed thus:

On 11/3/2009 2:20 PM Baron spake thus:

On Tue, 03 Nov 2009 00:27:20 -0800, David Nebenzahl
nobody@but.us.chickens>wrote:

And the fact that I don't have a terminator on the scanner might
not be helping, either. But as I said, when it works I can do
many scans with no problems.

Isn't the Snapscan internally terminated ? ie only has a single 25
pin data socket.

Nope; it has 2 sockets, and no termination switches that I can see, so
I'm ASSuming it's unterminated. (Most SCSI devices like this have two
sockets for daisy-chaining.)

Yes that is what I would go on. Single socket for self terminated and
two sockets if un-terminated.

--
Best Regards:
Baron.