The Case For Biquinary
|
From: Keith R. Williams on 31 Mar 2005 10:13 In article <vSK2e.26384$cg1.14245(a)bgtnsc04-news.ops.worldnet.att.net>, dcecchi_nospam(a)worldnet.att.net says... > > "Chris" <invalid(a)devnull.com> wrote in message > news:424A6DCF.B2FCD394(a)devnull.com... > > Mark Thorson wrote: > > > > > > I recently acquired an IBM 650 manual, and I was > > > interested to learn that it used a biquinary > > > representation for integers. This is a decimal > > > format, in which five bits represent the values > > > 0-4 or 5-9 and two binary bits select between > > > the upper and lower range of values. (In other > > > biquinary formats, a single binary bit may be > > > used to select between upper and lower.) > > > > > > > <snipped> > > > > Perhaps you mean 2 bits to decode any state ?. In the days of discreet > > transistor designs, it was a way of minimising parts count, and timing > > skew (counter is synchronous), thus maximising count frequency. Using > a > > Johnson counter configuration, the number of count states is equal to > > (stages * 2) and only 2 bits are required to decode any state. eg: a 5 > > stage counter counts to 10. Quite an old idea in fact and dates back > to > > tube days, when active device count really mattered. > > > > ISTR, an early HP counter from the 60's used a biquinary counter as a > > high frequency prescaler, but memory fades... > > > > Chris > > I would bet that the 650 had vacuum tubes, not transistors. Sorry I'm > too lazy to go to the archives at www.ibm.com and check. It doesn't say specifically (at least I didn't see it), but in 1953 I'd bet on vacuum tubes: http://www-03.ibm.com/ibm/history/exhibits/650/650_ch1.html I suspect that the 650-4 ('59), used transistors. Apparently everything IBM produced after the 608 ('55) used transistors: http://www-03.ibm.com/ibm/history/history/year_1955.html ....and a formal statement in '57 decreed "ever onward" transistors (from the above): "It shall be the policy of IBM to use solid-state circuitry in all machine developments. Furthermore, no new commercial machines or devices shall be announced which make primary use of tube circuitry." I'm surprised that you don't remember this stuff Del. ;-) -- Keith
From: Chris on 31 Mar 2005 10:44 Delbert Cecchi wrote: > > I would bet that the 650 had vacuum tubes, not transistors. Sorry I'm > too lazy to go to the archives at www.ibm.com and check. Am not to well up on IBM lore, but the earliest IBM machine I ever encountered was languishing in a scrapyard near Newbury (UK) in 1966 or so. I think it came from a USAF base which was closing. An IBM RAMAC machine, full of plug in modules and a movable head hard drive approx 5 feet high and with around 2 feet dia platters, all in a transparent perspex cover - a beautifull piece of engineering. The modules were around an inch and a half square on end and approx 8-10 inches long and contained a single tube (6211 double triode usually) and all the associated resistors to make a flip flop or gate. Still have some of the hundreds of recovered wire ended neon lamps from the thing somewhere. Quite young at the time, but with present knowledge and interests, should have made every effort to save the thing. Even had a fixed head cylinder hard drive which I cheerfully unscrewed all the heads from... Chris
From: Jon Beniston on 1 Apr 2005 06:25 jsavard(a)ecn.ab.ca (John Savard) wrote in message news:<a5b2b542.0503292349.26a162e8(a)posting.google.com>... > jon(a)beniston.com (Jon Beniston) wrote in message news:<e87b9ce8.0503290421.76e8451a(a)posting.google.com>... > > > Er? Even the smallest current FPGAs support tens of thousands of gates > > with the larger devices supporting hundreds of thousands. > > There. You see? You can't get an FPGA with as many gates as a Pentium > IV microprocessor. Maybe not, but you could put 100 32-bit RISCs CPUs into one. Cheers, Jon
From: John Savard on 1 Apr 2005 10:03 Keith R. Williams <krw(a)att.bizzzz> wrote in message news:<MPG.1cb5dd7ddb38942a989999(a)news.individual.net>... > In article <vSK2e.26384$cg1.14245(a)bgtnsc04-news.ops.worldnet.att.net>, > dcecchi_nospam(a)worldnet.att.net says... > > I would bet that the 650 had vacuum tubes, not transistors. Sorry I'm > > too lazy to go to the archives at www.ibm.com and check. > It doesn't say specifically (at least I didn't see it), but in 1953 I'd > bet on vacuum tubes: > http://www-03.ibm.com/ibm/history/exhibits/650/650_ch1.html > I suspect that the 650-4 ('59), used transistors. The IBM 650 computer very definitely used vacuum tubes. While new designs produced after a certain date may all have included transistors, this doesn't mean IBM stopped manufacturing its old vacuum tube designs. But there was an IBM 650 that used some transistors; from the BRL Report on Ed Thelen's site, I see that the IBM 650 RAMAC contained transistors. These, though, were in the add-on disk drive, not the 650 processor itself, which was still made in the preceding standard. A transistor and core-memory mainframe from IBM, the IBM 7070, was made with a design inspired by, but not strictly compatible with, the IBM 650. The details of this are in "The Architecture of IBM's Early Computers", from the September 1981 issue of the IBM Journal of Research and Development. The 7070, though, used 2 out of 5 bit code instead of biquinary. And the 7080 was the transistor version of the 705, thus adding to the incompatible architectures that IBM had before the 360. John Savard
From: Keith R. Williams on 1 Apr 2005 11:04
In article <a5b2b542.0504010703.1d8d013(a)posting.google.com>, jsavard(a)ecn.ab.ca says... > Keith R. Williams <krw(a)att.bizzzz> wrote in message news:<MPG.1cb5dd7ddb38942a989999(a)news.individual.net>... > > In article <vSK2e.26384$cg1.14245(a)bgtnsc04-news.ops.worldnet.att.net>, > > dcecchi_nospam(a)worldnet.att.net says... > > > > I would bet that the 650 had vacuum tubes, not transistors. Sorry I'm > > > too lazy to go to the archives at www.ibm.com and check. > > > It doesn't say specifically (at least I didn't see it), but in 1953 I'd > > bet on vacuum tubes: > > > http://www-03.ibm.com/ibm/history/exhibits/650/650_ch1.html > > > I suspect that the 650-4 ('59), used transistors. > > The IBM 650 computer very definitely used vacuum tubes. > > While new designs produced after a certain date may all have included > transistors, this doesn't mean IBM stopped manufacturing its old > vacuum tube designs. What about the official pronouncement in 1957 that no more products announced after that date would use ("primarily") tubes? Snipped from my earlier article: "It shall be the policy of IBM to use solid-state circuitry in all machine developments. Furthermore, no new commercial machines or devices shall be announced which make primary use of tube circuitry." The 650-4 was announced in 1959, according to the IBM archives. I dunno, though. I was in second grade. ;-) <snip> -- Keith |