Tested using "Raw block speed" test in LIDO 7 under MacOS:
[SCSI2SD v5]
READ: 891 KB/s
WRITE: 728 KB/s
[ACARD ARS-2000SUP]
READ: 1621 KB/s
WRITE: 1277 KB/s
More info:
The ACARD device contains a Samsung 850 Pro 128G SSD. The SCSI2SD contains
a Samsung Pro+ 64GB micro SD and is running firmware v4.6, IIRC. Both are
were attached to a Quadra 700 Macintosh running System 8.1 with 68 megs of
RAM (4 onboard + 64MB in 16MB SIMMS, the max on the Quadra 700). I had
them hooked up at the same time so I could use one to partition the other.
The hard disk "driver" was the one provided by LIDO, but I also tried
LaCie SilverLining 5's driver as well, but the performace was slightly
worse. I tested in LIDO using it's raw speed test feature. It's probably
only a rough measure of sequential speed. I just tested three times and
averaged the results, but it was within just a few KB/s each time.
Once I'm done I'll hook both of these up to a FreeBSD box, dd off full
backups, then start over again and try with ZFS under FreeBSD via a PCI
SCSI controller. Then again under IRIX if I still have the energy. I'll
give some results from 'fio' or 'iozone' under FreeBSD. Those will be a
lot more detailed and break down sequential versus random results and show
the results of various other permutations.
I'd also like to test the SCSI2SD v6, but I can't get my hands on one,
yet. The only place that talks about the v6 is the codesrc wiki and the
American ebay retailer seems to only have the v5.0. I'll wait, I guess.
-Swift
Hi, All,
A friend of mine who is mostly into Sun equipment recently purchased a
MicroPDP-11 from a State auction. He knows little about DEC gear, but
I can help him there. His machine had the RD5X drives pulled by the
State, but still has an RX50. Where can I point him to get a handful
of RX50 floppies? I can help him with contents to put on them, but he
needs media.
He's likely to start with RT-11. He could probably use 10-20 floppies to start.
Thanks,
-ethan
I took apart my VR241 recently to see if I could find the reason why the
screen doesn't go completely black. I took lots of pictures while doing so,
to make sure I could put it back together again correctly. However, now that
I am putting it back together, there is one wire which looks like it wasn't
connected. It is on the deflection board (on the right when looking from the
back of the CRT).
I am not sure now if I missed taking a photo of this when it was connected,
or if it really should be not connected. There is a pin marked Size Link
near to it, which might be where it has to go, and sounds like an optional
thing if that is the case.
You can see the wire in question at the bottom of the picture below, it is
the green wire with a single-pin connector on it, and the size link
connector is the two-pronged connector just below it in the photo:
https://1drv.ms/i/s!AlQc3lJwQx7bgbAJQx-HsvGY8Gcqsg
Anyone know where this wire should go?
Regards
Rob
Hi All,
In bringing up and debugging my PDP 11/45, I found that one of my GRA
(M8101) spares has a failed ALU subsidiary ROM. It's a pretty standard
little 32x8 ROM in a 16-pin DIP, and the truth table is in the 11/45
print set.
I wonder what the replacement options are for parts like these? In
particular, given the 30ns micro-cycle on the KB11-A, and the fact that
the propagation time for the ALU downstream of this is roughly 20ns on
its own, I'd be worried that an off-the-shelf bipolar PROM might be too
slow here.
I'm still a little slow on reading the microcode flows, so its not clear
to me exactly how many micro-cycles there are on the critical path for
the E-class instructions where this ROM is used. Maybe its not an issue.
Anybody every try replacing one of these with a bipolar PROM? Any other
suggestions for how to repair parts like these?
cheers,
--FritzM.
> From: Richard Loken
> I have an Ann Arbor Ambassador here with the original owner's manual.
If anyone else has _another_ AAA, I'd like one too! (I'm assuming Ian's going
to be getting this one! :-)
They were wonderful terminals, in their day - the largest screen of any
terminal easily available at the time. People in Tech Sq preferred them to
VT*, etc for that reason.
Noel
> From: Glen Slick
> the part is listed as DM8598-AD, where a DM8598 is a 256-bit (32x8)
> tri-state bipolar mask ROM.
> Some substitute T.S. PROMs include the Signetics 82S123
On my M8101, it's an 82S123, which is a tri-state programmable PROM (the
82S23 is the open-collector version of that chip). Those should be relatively
easy to obtain.
BTW, quick question: if a fusible link PROM 'fails' because one of the
fusible links regrows, is it possible to 're-program' that particular chip,
back to the 'original contents'? Some programmers might barf (because they
want the chip to be 'empty' to start with'), but maybe one of those home-brew
pgrogrammers could 'refresh' the chip (thereby avoiding using up a new chip,
when it's not really needed)?
> From: Curtis H. Wilbar Jr.
> Is there a file containing the image ?
I'd really like to accumulate a database of the contents of all the PROM
components for all the PDP-11 CPU's. I've got a few of them (for the -11/05),
but there are zillions more.
Anytime anyone creates one, can you please send me a copy, and I'll try and
get them organized and uploaded (and if I _really_ get ambitious, I might try
and start filling in the gaps).
Noel
> From: Swift Griggs
>> Much of the architectural concept was shared with IBM 7030 STRETCH
>> (another system worth researching).
> Hmm, I've never heard of it. I'll check it out.
The first supercomputer, IMO. It's an interesting machine, with a variety of
innovations that later became standard: e.g. it has separate instruction and
arithmetic units, with the former being in charge of all fetches, both
instruction and data, as well as executing things like branch instructions;
it also has a primitive form of pipelining ("Interlocks in the look-ahead
unit ensure that nothing is altered permanently until all the preceeding
instructions have been executed successfully.")
Eric has a nice page about it:
https://www.brouhaha.com/~eric/retrocomputing/ibm/stretch/
There's a good book about it:
Werner Buchholz (editor), "Planning a Computer System: Project Stretch",
McGraw-Hill, New York, 1962
Speaking of books, there's also a CDC 6600 book:
Jim E. Thornton, "Design of A Computer: The Control Data 6600",
Scott, Foresman, Glenview, 1970
Really gotta do that Bibliography!
Noel
Someone emailed me last night that has a full set (about 30+) of manuals in
grey binders for VMS 5.0.
Still waiting for them to respond with their location. This is not something
I'd want...
J
It's been a long time since I've asked about this, so I figured it was
worth another shot. I've been looking for an Ann Arbor Ambassador
terminal for close to fifteen years, with no success. It's kind of an
obscure model, but they did exist. I heard of one being available
several years back, but, unfortunately, someone else got it before I
could.
So, does anyone have one of these? Has anyone seen one in recent memory?
-Ian
I've been saving the VT52 I've owned for years (used it with a modem
back in the late 80s to dial into school) with the thought of paring it
up with a PDP-8/E, PDP-8/F, or PDP-8/M .... but I don't know that the
PDP-8 train will ever stop here. I've come close a couple of times, but
have either missed the train on a good deal, or not been in a position
to stomach the pricing some of them fetch.
So, I'm contemplating selling the VT-52. It has age typical wear, but
last time it was powered on, it was working. There was a touchy
connection that would act up once in a while requiring a tap on the side
to bring it back around (something in the video connection no doubt). I
never dug into it to resolve it 100%, as it didn't happen often, and a
'love tap' on the right side always brought it around.
I'd like to hang onto it, but it is big.
I'm entertaining offers which might sway my decision to keep/sell it.
I'm located close to the intersection of Sharon, Easton, and Stoughton,
MA.
I don't think shipping is an option, unless your willing to pay, and
take the risk on something like this being transported. If I can get a
big enough box, I can pack it well.... but I'd prefer not to do it due
to the risks involved.
Keep VT52 in the subject line of any e-mail you send so I can find it
easier. Sometimes I may only check mail here once a week, so if you are
inquiring and don't hear from me for a while, no fear, I'll get around
to you.
-- Curt
