test-drb

test-drb@ccmp.vtda.org

101090 discussions

by steven＠malikoff.com

Looks like the recent recovery in Germany had a precedent. These two happy guys have lugged their 360 out of the building BUT look at the extra they snagged with theirs, and in great condition too! https://www.ebay.com.au/itm/1965-TORINO-Prototipo-auto-GIULIA-SPORT-Special… ;)

7 years, 2 months

One of the deeper dives into RISC vs CISC I've seen

by jnc＠mercury.lcs.mit.edu

I finally got around to reading that note. My principal reponse is that it got so far down into details that I couldn't see the larger picture any more. Going back to the original IBM 801 work, the RISC concept is very simple: to make the overall system as fast as possible; it did this by making the CPU cycle time as short as possible. This results in a CPU that is not as easy to work with; therefore the compiler has to be 'smarter'. In other words, engineering complexity is moved from the hardware to the software. This is an an acceptable tradeoff; the complexity in the software is not a recurring cost, whereas extra gates add cost to every machine produced. Moreover, while the more complex compiler may be more time-consuming to run, that cost is only paid once, whereas the efficiency of the binary is felt every time the program is run. Focusing on what features a CPU does or does not have in some ways misses the whole point of RISC: it's not about what specific features the CPU has, in isolation; it's about looking at the system as a whole, all the way up through the compilers, to maximize performance. I recall Tom Knight laying out the implication for CPU design very simply, in a seminar I took back when the idea had just come out: look at the CPU design, and find the longest signal path; this will set the lower limit on the clock time. Redesign to remove that path; since the capability that needed it will inevitably be used only part of the time, the execution increase caused by losing it will be outweighed by the speedup of all the other instructions. The other thing one needs to remember, talking about RISC, is that it's now been almost 40 years since the concept was devised (an eternity in the computing field), and the technology environment has changed drastically since then. So RISC has changed and adapted as that environment changed. Nowadays, when people throw a billion transistors at each CPU, the picture is somewhat different. Register widows were just the first instance of this sort of thing; we have this unused area of the chip, what can we put there? >> On 6/15/19 3:40 PM, ben via cctalk wrote: >> CISC design is now needed to handle the 'extended features'. ... RISC came >> along only because Compilers could only generate SIMPLE instructions, that >> matched the RISC format. No; compilers had been created that could use the more complex CISC instructions of, say, a VAX. RISC post-dated a lot of those developments, and had an entirely different point. > From: Chuck Guzis > For what it's worth, the number of instructions in the ISA does not define > RISC, but rather that the instructions execute quickly. Some RISC > implementations have large instruction sets. Right; what's reduced is the complexity of the instructions, which leads to the speedup which is the goal, not the number of them. In fact, a RISC CPU may actually have more instructions, e.g. separate ones for different cases, with the compiler being given the responsibility of picking the right one, instead of the CPU figuring it out as it goes. > RISC does carry a penalty in that you're executing more instructions to get > something done, so your code space is larger; but, you hopefully have them scheduled > such that the whole task runs faster. This in another aspect, which I've mentioned before, behind the rise of RISC, which is the changing size and speed of main memory, relative to the CPU. Simpler instructions are faster, but a given task will need more of them. This is acceptable if the memory can supply them fast enough. If the memory bandwidth is less, more complex instructions make sense, to get more out of the limited bandwidth. Also, if memory is of limited capacity, or expensive, then more complex instructions make sense, since more can be done with a fixed amount of memory. (The PDP-11 still scores very high in code density.) This too, however, has been overtaken by the march of technology. Still, the basic idea of RISC still applies; make the CPU clock rate as fast as possible by making the instructions simple, and let software deal with the resulting issues. Noel

7 years, 2 months

Old DEC stuff in Bedford MA

by sales＠elecplus.com

There is an elderly gent in Bedford, MA that was a DEC dealer back in the day. The following inventory is what he has posted on a service I belong to. He is very deaf, and he can't hear me over the phone. He is open 9-5 M-F. Someone needs to go and dig. I don't think he knows where everything is anymore, and I don't think he can reach high places or lift medium-heavy things. Not affiliated with seller, etc. Charlie Burgess 119A Great Road Bedford, MA 01730-2720 781-275-6800 qeiinc at verizon.net 0132727 03-211265-0 06-888E7620 06-98805420 06-98826020 06141 10-09397-01 10-13102-00 10028002 10028102 10058100 10104 101066 10183/10184 109831-00L 11-10364 11/23-AW 11/34A-HC 11/730 11/750-CA 11/84-AC 1110 11130-DC 11150-CH 11213 11214 11592-906-1 117838-A 12-04403-01 12-09403-01 12-10152-0 12-11196-02 12-11477 12-11519 12-11563 12-11580-01 12-11581-00 12-11583-00 12-11583-01 12-12157-00 12-12199-00 12-12904-00 12-13097-00 12-13185-00 12-13186-00 12-13369-00 12-13686-00 12-14333-JO 12-14360-00 12-14614-02 12-15050-00 12-15292-00 12-1529600A 12-15297-00 12-15336-00 12-15336-08 12-15336-11 12-15360-00 12-15394-00 12-15558-00 12-15633-00 12-15663-00 12-16166-00 12-16166-02 12-16308-00 12-16391 12-16552 12-16827-00 12-17431-00 12-17431-01 12-17474-00 12-17606 12-18320 12-18416-00 12-18633-00 12-19245 12-19245-00 12-19245-01 12-19266 12-20267-01 12-22196-01 12-22196-02 12-22271-01 12-22707-01 12-23196-01 12-23607-04 12-23609-04 12-23609-11 12-23609-15 12-23609-19 12-23609-21 12-24701-10 12-26339-01 12-27591-01 12-28258-01 12-28508-01 12-29258-01 12-29635-01 12-30552-01 12-32022-01 12-32728-01 12-33626-01 12-35173-01 12-35759-01 12-39921-02 12-45246-03 120119-01 123 1351922 13C27A-30 1412DA 16-12256-0 16-12398 16-12497-01 16-1389700B 16-14110-00 16-17186-01 16-19001-01 1616-010 1632TTL 1664ATTL 17-000-82-0 17-00004-00 17-00079-00 17-0008202D 17-00083-06 17-00083-10 17-00083-37 17-00083-49 17-00087-00 17-00100-00 17-00107-01 17-00193-00 17-00198-15 17-00233 17-00254-00 17-00254-01 17-00277-04 17-00280-00 17-00282-00 17-00282-01 17-00282-03 17-00284-00 17-00285-00 17-00285-02 17-00286 Cindy Croxton Electronics Plus 1613 Water Street Kerrville, TX 78028 830-370-3239 cell sales at elecplus.com --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

7 years, 2 months

Software for Fairy YL-23 IC tester wanted

by roelof_klaas＠yahoo.com

Hello fellow collectors, I have this Fairy YL-23 IC tester / programmer with ISA bus. http://matthieu.benoit.free.fr/Fairy_YL-23_Eprom_Programmer_resources_page.… The problem: I have no documentation and no software for it. Can anyone help me getting PC software for it? Thanks in advance!Regards, Roland Huisman

7 years, 2 months

List search option?

by jesse＠cypress-tech.com

Is there a list search option on the archives? As in if I wanted to find a relevant thread for part number ABC123 I could search that somewhere?

7 years, 2 months

Data General Eclipse S140 for sale in Fremont

by sellam.ismail＠gmail.com

Hello Folks. I'm just passing along this ad I came across whilst perusing Craigslist: https://sfbay.craigslist.org/eby/clt/d/fremont-s140-data-general-eclipse/69… Asking price is $1,500. I have no relation whatsoever to the sale or the seller, just passing along. Sellam

7 years, 2 months

PDP-11/23 for sale in Portland OR

by scott.l.baker＠gmail.com

The system consists of: 1) a 19" rack-mountable CPU chassis 2) a 19" rack-mountable floppy-disk drive (and bootable RT-11 floppy-disks) 3) Zenith Z-29-A RS232 terminal The boards included are: M8186 KDF11-A 11/23 CPU ????? 256KB parity RAM ????? DSD-440 floppy disk interface ????? bus grant continuity card M8028 DLV11-F Async interface M8012 BDV11 Bus terminator, bootstrap and diagnostic ROMs M8016 KPV11 Power fail, realtime clock, (termination) Also included are several 8" floppy disks with RT/11 and other system software. If interested, send me a message. Thanks, Scott

7 years, 2 months

Value of Burroughs B9974 disk pack

by aperry＠snowmoose.com

When I worked for Burroughs/Unisys, I was one of the last people working on software for B1000. I think I was the sole user of the B1965 at their Lake Forest (Orange County) California office in '88-89. I was surrounded in my cubicle by all of the disk packs for that system. My favorite systems while at Burroughs was the B1000s. One of those type of disk packs is up on eBay right now and I am trying to decide whether to buy it. It is $60 plus another $40 for shipping. Is that too much? I almost never see Burroughs stuff, so, if I want Burroughs stuff, I should just get it, right? alan

7 years, 2 months

Value of Burroughs B9974 disk pack

by jnc＠mercury.lcs.mit.edu

> From: Alan Perry > a chance to see and touch something that I haven't seen in decades > that was once a big part of my life. I know exactly what you mean. PDP-11's were a huge part of my professional life: -11/20: the first computer I actually used, in high school -11/45: the computer on which I took my first programming course in the CS Dept (amazingly, my group later traded the next computer for that very computer, years later) -11/40: the first computer that was 'mine', in the sense that I controlled it -11/70: the computer I did a lot of my early Unix learning/work on -11/03: my first packet switch code ran on one of these -11/23: the most widespread machine that my early packet switches ran on -11/73: the timesharing machine at the company that productized my packet switch code I'm very fortunate to now have a lot of PDP-11's in my collection. (Including an /04 and a /34, machines I never used BITD.) I had no contact with PDP-11's for many years, but only a few years ago someone here gave me an -11/84 (if I drove to Wisconsin to get it :-); I stopped off at my in-law's house to overnight on the way back with it, and they later told my wife it was the happiest they'd ever seen me! Noel

7 years, 2 months

Modems and external dialers.

by jnc＠mercury.lcs.mit.edu

> From: Liam Proven > Now, my tablet and iPhone and Android phones need *at least* 3 or 4 > apps updating every day. ... The OS needs to be replaced every month > or two to fix all the flaws in it, and that's a gigabyte or so of > storage. > I am *furious* about this. > ... > I had a better *phone* and a better *PDA* 20 years ago. Great rant. I myself much prefer my Windows98 machines to my Windows 10 laptop, which I had to buy because i) many Web sites won't work without the latest and greatest browser (in many cases because of the nitwitted craze for not just HTTPS, but the latest and greatest security option for it - but let me not get derailed into that rant into lemming-like stupidity), and those are only available for the latest and greated bloatware OS. Noel

7 years, 2 months

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