Evening folks,
I have two so-called Logic Analysers, both cheap Chinese clones of other
more expensive units that hook up to the host via USB2 and stream readings
direct to software, in one case the open source Sigrok and in the other
genuine Saleae Logic.
I'm getting different and inconsistent readings out of both of them whilst
sampling at 25MHz which should be more than enough for this 6MHz Executel
I'm working on. Both of them are good for spotting dead or stuck outputs but
I still can't get a good set of readings from eg all points on a single
address line. Tonight I replaced all four ROM sockets and ROM chips, tested
each individual line for resistance (0.5 ohms on all apart from an
occasional 0.4 and 0.6) but still get ghost readings.
Is it me or the cheap clones?
Whilst looking for better quality units I came across a couple of 'proper'
HP/Agilent analysers, a 1663A 34 channel and 1661A 102 channel which seem
complete apart from the chip leg grabbers. Am I right to assume some of you
might have experience of these beasts?
Forums seem to mostly think the streaming USB units aren't worth anything
for more than a few channels but I'm still a relative beginner to all of
this. I really need to watch all 16 lines of an address bus and externally
clock it as Tony has suggested.
Any insights appreciated!
--
Adrian/Witchy
Binary Dinosaurs creator/curator
Www.binarydinosaurs.co.uk - the UK's biggest private home computer
collection?
We have one last 60-minute spot to fill for the Friday (March 31) tech
classes at VCF East. Any topic is fair game if it has wide appeal and
makes people into better vintage computing hobbyists. The topics thus
far are here: http://vcfed.org/wp/classes/. Email me ** off-list ** if
you'd like to volunteer. (Please avoid "someone should teach XYZ"
messages -- we know what * should * be taught, we need people to DO it. :)
________________________________
Evan Koblentz, director
Vintage Computer Federation
a 501(c)3 educational non-profit
evan at vcfed.org
(646) 546-9999
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> From: Paul Koning
> Another OS that would run on your machine (as well as an 11/20) would
> be RSTS-11 (V4, or I suppose V3 if you can find that)
I'd love to have an old RSTS-11, is there any variant around?
> didn't use the MMU
Huh? He's got an MMU (I think): it's the EIS he's currently struggling with.
Noel
Can someone please fix the mailing list software? This has been
reported every once in a while by a bunch of people for over ten
years.
These are a just the last bounces I got:
20-Jan cctalk-request at classiccmp [78] confirm fd5d1f938a6c920c61c094802694d0194e87f1a4
25-Jan cctalk-request at classiccmp [78] confirm e01809296377d0fd3033b4ab27394ca7dc0fae71
31-Jan cctalk-request at classiccmp [78] confirm 38290c8a992491eda604beff5a06ff20cd7e85f5
> From: William Degnan
> I was able to get the extended three cables
Excellent!
> I can put the M7238 EIS card on a riser so I can probe for faults
I'm all agog to hear what you find out!
> and maybe if I am lucky boot XXDP+. With the EIN installed I can't boot
I thought the machine basically just totally froze if you tried inserting the
KE11-E, and removing the jumper to enable it? Oh well, that severe a fault
should be fairly easy (sic) to track down.
> From: Paul Koning
> DEC's PDP11 architecture handbook doesn't appear to confirm that.
> Either that or the model differences table is sloppy.
The next page (B-4) says "The KE11-E .. provides MUL <etc>" and has an
"x" under "35/40".
Noel
> From: Allison
> for laughs I wandered over to:
> http://ftp.math.utah.edu/pub/mirrors/minnie.tuhs.org/PDP-11/Boot_Images/
> To see if the copy of V6 on RL02 is still there.... yep it is. and it
> runs on a 11/23 just fine
Yes, that's another copy of the Shoppa disk.
So, I looked at that system, to see how it dealt with the clock issue on an
11/23 (in /sys/ken/main.c, if anyone else is interested). While looking, I
noticed something that made it extremely unlikely that it would boot on an
11/40. Sure enough, attempting to boot the /unix on it on a (simulated) -11/40
blows out.
There are a couple of other unix loads on that pack image (oldunix, unix.tmp,
etc), but all the ones I looked at had the same issue (only tried booting the
'unix' one, though); they're probably all for the same machine, so have the
same configuration issue.
V6 Unix was pretty persnickety about the hardware configuration it ran on;
while it was possible to create builds that would run on almost any
configuration, on 'vanilla' V6 that really only applies to the /40/45/70
era. And even then you still had to re-build the system to match your actual
hardware configuration, almost all the time.
The advent of the /23 (with no CSW, and no KW11-L/P), made things more
complicated. (The clock is pretty key - Unix needs one - several things,
e.g. parts of the teletype drivers, require real-time delays provided by the
clock. I've never tried to run Unix without a working clock, I'm not sure if
it would run without slowly grinding to a halt as stuff waited for clocks
delays that never happened.(
With a little work, a suite of 'universal boot' versions (one for each type of
disk controller - RK05/RL02/RX02 etc) could have been created that would boot
and run on any pretty much CPU/etc configuration - at least, well enough to
build one that did exactly match the hardware configuration at hand. (The one
on the Shoppa disk is close, from what I could see.)
I don't think anyone ever bothered, though (in part because it was much more
of a PITA to test them all, BITD, with only real hardware).
Noel
> From: William Degnan
> my focus has been on just getting an 11/40 hardware working
Rightly and properly so...
> I suppose I should be happy with RT-11 given my circumstances.
Unix really is a significant improvement, we really need to make sure you can
run it. Don't worry about the OS image issue, I can crank them out like
sausages, and we already have all the bits we need (V6 RL driver, bootstrap,
etc).
> It's not possible with the 3 over the back cables to put the 7238 on a
> riser card to probe signals as easily.
Really? DEC specified BC08R-01 cables, which _should_ be long enough to allow
it to be put on an extender. Does your machine have the -01's, or have they
been replaced with little shorty ones?
If the latter, if you can't find any -01's, it should be possible to locate
some generic 40-pin cables, which should work (old IDE cables should work,
but not the new ones, which have a key that will prevent the connectors from
going in, in this application).
Also, it should not to be too hard to whip up some: the connectors and the
flat cable are pretty easy to find - although not the ground-plane backed
kind - do anyone know of a source for that? Anyway, the regular kind of flat
cable ought to work well enough for debugging.
Noel
Hi,
I am looking to swap or buy the following HP-Integral IPC (portable HP-UX box) interface boards:
- HP-IL interface
- 1 MB memory board
Does anybody have a manual for the HP-IL interface board?
Could offer HP 9000 interface or memory boards.
Martin
Hi,
Can someone identify this circuit board? It's some sort of magnetic core
memory. I've had this for ages and I've always wondered what it is and
where it comes from.
http://lookpic.com/O/i2/366/iAFq4mLF.jpeg
Best regards
> From: Allison
> for laughs I wandered over to:
> To see if the copy of V6 on RL02 is still there.... yep it is.
There are actually plenty of builds out there that run on RL11s, e.g.:
http://www.tuhs.org/Archive/PDP-11/Distributions/other/Tim_Shoppa_v6/
includes "A V6 RL02 bootable on a 11/23. Kernel is built for a 11/23, 2
RL02's, and 2 RX02's"; and my V6, running under Ersatz-11, is also an
RL-based system.
The real issue with mixing and matching kernels and disks is that since the
RL was not a standard device (as far as 'mkconf' went), the RL's can have
different major device numbers on different systems.
This does not stop the system from _booting_, since internally there will be
consistency, but consistency between the OS and file system is another
matter: e.g. trying to mount another drive (or any other use of /dev/rl? or
/dev/rrl?) may not work, since the device inodes for /dev/rl? might have the
wrong major device numbers in them.
> and it runs on a 11/23 just fine
Must be a slightly modified V6 - totally stock V6 will panic when it can't
find a clock (unless there's a BDV11), or NXM when it tries to touch the
switch register.
And for machines with no BDV11, I had to turn the clock off while booting;
the first time I tried to boot on a simulated 11/23, my totaly stock vanilla
V6 apparently took a timer interrupt during the boot process and went wayyyy
South, totally smashing the file system in the process. Not sure how the one
above dealt with this...
Noel
