> From: Pete Lancashire
> NO PACKING OR SHIPPING, must be local pickup.
Just a reminded to everyone; most PakMail franchises are prepared to go
somewhere off-site, pick items up where they sit, and then pack them; I've
used this service several times for 'pick up only' items.
Noel
Hey, all, the RK11-D contoller for the PDP-11 uses Motorola 4015 MSI chips on
one of the boards (M7254), but I can't find out anything about them. Google
didn't turn anything up, and the appendix in the RK11-D Maintenance Manual
that has info about 'all' the MSI chips used in the RK11-D doesn't have this
one. It appears to be a quad flop - anyone have more info? Thanks!
Noel
> From: Pete Lancashire
> Pak Mail is not cheap
Actually, since they buy 'in bulk' from carriers, they are surprisingly
reasonable; their quote to ship an H960 rack from Arizona to me was less
than I was quoted by some carriers.
Noel
> From: Yvan Janssens <ik at yvanj.me>
> ...
> I'm located at the other side of the planet.
> Would PakMail work for that as well?
Pakmail can _send_ to most countries (they can only do _pickups_ in the US
and Canada, that I know of), but of course sending a large object a long way
can be expensive. I don't know if they can do surface (i.e. boat) to
destinations outside North America, or just air - check their Web-site.
Noel
>
> Date: Wed, 9 May 2018 13:08:51 -0400
> Subject: Re: Sparc Laptops
>
> I have a pretty cool DEC 486 laptop. I am unsure if they made a Pentium
> laptop before they were bought out.
> http://www.vintagecomputer.net/digital/DECpc_433SLC/
> DECpc_433SLC_Premium_open2.jpg
> b
>
> On Wed, May 9, 2018 at 11:46 AM, Zane Healy via cctalk <
> cctalk at classiccmp.org> wrote:
>
> > I dream of owning an Alphabook. It?s a silly dream, but it?s one I dream
> > anyway.
> >
> > I have a Sparcbook 3GS (I think that?s the model) somewhere.
> >
> > Zane
>
I have about 15 SPARC based lugables and laptops. Some are TRIgem/RDI
Britelites that have an IPC/IPX/LX motherboard inside, three Voyagers, the
rest are Tadpole SB2, SB3, SB3GX, and Ultrabooks.
Michael Thompson
Maybe not old enough? Not affiliated with seller, etc.
WTS:
(6) Like new Tadpole/RDI/Cycle UltraSPARC II/e Laptops
UltraSPARC 500MHz CPU
2GB Memory
60GB Disk
Complete and tested with AC Power Supply
?Make Offer
george at datalease.com
Best Regards,
George Seldin
Datalease Systems
(714) 632-6986 x200
george at datalease.com
Cindy Croxton
Electronics Plus
1613 Water Street
Kerrville, TX 78028
830-370-3239 cell
sales at elecplus.com
AOL IM elcpls
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
> Looking at modern hard disks, I'm unconvinced we could even mass-produce
> something like that today.
>
> A 40mm radius is comparable to a 3.5" disk, which are generally 5,400-7,200
> RPM. 15,000 RPM is the fastest available, but those tend to be low-capacity and
> expensive, and are often 2.5" drives with a huge heatsink. We could perhaps
> rotate a very narrow smaller cylinder faster still but then the capacity
> suffers further, and the seek time would start to dominate.
I Am Not An Engineer(tm) but it seems to me that a taller cylinder
should be less prone to wobbling on its axis than a flat disk,
particularly if it's built at the scale of the drums I've seen at the
CHM where there's room enough to really bolt that sucker down. Bit
different than a 3.5" box with a stack of thin metal platters in it,
I'd think.
I wonder how the late generation paging disks (fixed head per track) like DG used in the 80's compared?
-----Original Message-----
>From: Paul Koning via cctalk <cctalk at classiccmp.org>
>Sent: May 10, 2018 7:29 AM
>To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>Subject: how fast were drum memories?
>
>Drums were used as main memory in a number of early computers, and as secondary memory for a while longer. I wonder how fast real ones (actually constructed) managed to be.
>
>What prompted this question is reading an interesting document: https://ir.cwi.nl/pub/9603 (in Dutch), "Principles of electronic calculating machines, course notes February 1948" by Prof. A. van Wijngaarden at the Mathematical Center (now CWI) in Amsterdam. It's quite a fascinating short introduction into computing technology of that era. (One comment in the intro: "The field is new. At the moment, the Eniac is the only working machine..." -- probably not quite accurate given some classified machines, but not too far wrong.)
>
>The section on main memory describes a bunch of different technoly possibilities, one of them drum memory. He writes that a drum of 8 cm diameter (a bit over 3 inches) and "a couple of decimeters height" could hold maybe 100k bits, with a track pitch of "a few millimeters". So far so good. He goes on to suggest that such a drum might spin at 1000 revolutions per second, i.e., 60,000 rpm. That seems amazingly high. I could see it being physically possible for a drum of only 40 mm radius, but it sure doesn't sound easy. It's a good goal to strive for given that the logic, even in the days of vacuum tubes, can run at cycle times of just a couple of microseconds. As one more way to speed things up he suggests having multiple rows of read/write heads, where the addressed word would be picked up by whichever head sees it soonest. 10 rows and 60k rpm would give you 50 microseconds average access time which "even for a parallel computer would be a very attractive number". (Pages 17-18)
>
>I'm wondering what the reality of fast drum memories looked like, and whether anyone came even close to these numbers. Also, am I right in thinking they are at least in principle achievable? I know I could run the stress numbers, but haven't done so.
>
> paul
>
Back in the 1970s and 80s, my brother and I used to frequent computer
swap meets in and around Orange County, CA. We both built S-100 systems
>from the boards we bought there. I sold mine long ago, but my brother
kept at it for several more years. Last December he passed away, and I
discovered that he had kept his "big" system, and had put together a
second as well.
I'm interested to know people's thoughts on what they might be worth,
both as complete systems, which I would prefer, and if sold as
individual components. Everything is located in Santa Ana, CA.
My brother was a fan of OASIS, so his main machine was switch-selectable
to boot either that or CP/M (MP/M). It was almost certainly running when
it was decommissioned (which would have been at least 20 years ago).
OASIS Box
Large (as in washing-machine) enclosure containing:
Four 1/2-height, eight inch floppy drives, in enclosure.
Two eight inch hard drives, probably 10 or 20 MB each, in enclosure.
18-slot CCS mainframe with these cards:
CCS 2805, Rev. D, Terminator/Wallclock (terminator unpopulated)
CCS 2830 Six/SIO, Assy No. 02830-00001, Rev. A
CCS 2832 2 Rev. A, Winchester disk controller (2-board set). Module
9016-Rev02, 7-82.
CCS 2422 Assy No. 02422-0001 Rev. B, Multimode Floppy Disk Controller.
CCS 2066 Rev. B 64K Dynamic RAM, bank selectable
CCS 2066 Rev. A 64K Dynamic RAM, bank selectable
Cromemco 16KZ
Cromemco 16KZ
CCS 2068 Assy No. 02065-00001 Rev. C 64K dynamic Memory
Computer System Resources (CSR) RAM 64D, modified w/external switch(es)
CCS 2820 Assy. No. 02830-00001 System Processor
CCS 2704 Assy No 02704-0000? Rev. ? Terminator Board
The other system is just the mainframe. The manufacture's label is
hidden by the floppies and I was too lazy to remove them to read it.
Black Box
12-slot mainframe, with two 1/2-height 5.25 inch floppy drives (and room
for two more).
Includes these cards:
CCS 2066 Assy. No. 2066-00001 Rev. A 64K Dynamic RAM, bank selectable
CCS 2820 Rev. B System Processor
CCS 2066 2.2K Rev. C 64K Dynamic RAM, bank selectable
CCS 2066 Assy. No. 2066-00001 Rev. A 64K Dynamic RAM, bank selectable
CCS 2066 2.2K Rev. B 64K Dynamic RAM, bank selectable
CCS 2422 Assy No. 02422-0001 Rev. B, Multimode Floppy Disk Controller.
CCS 2805, Rev. D, Terminator/Wallclock (terminator unpopulated)
Konan SMC200 P-SMC-201-A Hard disk controller (no hard disk)
CCS 2830 Six/SIO Rev. C
CCS 2704 Assy No 02704-00001 Rev. C Terminator Board
Separately, he also had:
CCS 2520K Extender/terminator board kit, unassembled, in box with
manual.
Archive Corporation Sidewinder tape drive with two tapes.
Cromemco 16KZ RAM board, with manual
I have photos of everything.
Thanks,
-Nick