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Looking for old microprocessors
Does anybody know where I can get a Harris or Intersil
HD6100, HD6120, IM6100, or IM6120 microprocessor (cmos pdp-8)? I used to work for Digital, and thought it would be an interresting project to homebrew a PDP-8 system. I have a T11 microprocessor chip in the junbox someplace, so a PDP-11 system is also a possibility. |
No cheating! If you're going to homebrew a PDP-8, you have to build it out
of discrete TTL. 73, Dave, AA6YQ Data General, 1972 - 1981 Designer of the Nova 2, Nova 3, MP200, and microEclipse CPUs, as well as some parts of FHP and EGO "kenneth scharf" wrote in message ... Does anybody know where I can get a Harris or Intersil HD6100, HD6120, IM6100, or IM6120 microprocessor (cmos pdp-8)? I used to work for Digital, and thought it would be an interresting project to homebrew a PDP-8 system. I have a T11 microprocessor chip in the junbox someplace, so a PDP-11 system is also a possibility. |
No cheating! If you're going to homebrew a PDP-8, you have to build it out
of discrete TTL. 73, Dave, AA6YQ Data General, 1972 - 1981 Designer of the Nova 2, Nova 3, MP200, and microEclipse CPUs, as well as some parts of FHP and EGO "kenneth scharf" wrote in message ... Does anybody know where I can get a Harris or Intersil HD6100, HD6120, IM6100, or IM6120 microprocessor (cmos pdp-8)? I used to work for Digital, and thought it would be an interresting project to homebrew a PDP-8 system. I have a T11 microprocessor chip in the junbox someplace, so a PDP-11 system is also a possibility. |
Boy -- Have you got little to do, or what!!!!
"Dave, AA6YQ" wrote in message news:lARab.522300$YN5.348403@sccrnsc01... No cheating! If you're going to homebrew a PDP-8, you have to build it out of discrete TTL. 73, Dave, AA6YQ Data General, 1972 - 1981 Designer of the Nova 2, Nova 3, MP200, and microEclipse CPUs, as well as some parts of FHP and EGO "kenneth scharf" wrote in message ... Does anybody know where I can get a Harris or Intersil HD6100, HD6120, IM6100, or IM6120 microprocessor (cmos pdp-8)? I used to work for Digital, and thought it would be an interresting project to homebrew a PDP-8 system. I have a T11 microprocessor chip in the junbox someplace, so a PDP-11 system is also a possibility. |
Boy -- Have you got little to do, or what!!!!
"Dave, AA6YQ" wrote in message news:lARab.522300$YN5.348403@sccrnsc01... No cheating! If you're going to homebrew a PDP-8, you have to build it out of discrete TTL. 73, Dave, AA6YQ Data General, 1972 - 1981 Designer of the Nova 2, Nova 3, MP200, and microEclipse CPUs, as well as some parts of FHP and EGO "kenneth scharf" wrote in message ... Does anybody know where I can get a Harris or Intersil HD6100, HD6120, IM6100, or IM6120 microprocessor (cmos pdp-8)? I used to work for Digital, and thought it would be an interresting project to homebrew a PDP-8 system. I have a T11 microprocessor chip in the junbox someplace, so a PDP-11 system is also a possibility. |
Talk about bad timing ....
Just a couple of days ago two friends of mine hauled a PDP/8 out to the dump. Of course, you might not have been able to afford the power to run a REAL PDP/8. I never actually worked with an 8, although I did publish a paper on 11M crash dump analysis. Might be fun to be able to grok a little Macro-11 from time to time ... hmmm ... wonder if there's a Pro350, or even an old 11/44, languishing in someone's basement. ... "kenneth scharf" wrote in message ... Does anybody know where I can get a Harris or Intersil HD6100, HD6120, IM6100, or IM6120 microprocessor (cmos pdp-8)? I used to work for Digital, and thought it would be an interresting project to homebrew a PDP-8 system. I have a T11 microprocessor chip in the junbox someplace, so a PDP-11 system is also a possibility. |
Talk about bad timing ....
Just a couple of days ago two friends of mine hauled a PDP/8 out to the dump. Of course, you might not have been able to afford the power to run a REAL PDP/8. I never actually worked with an 8, although I did publish a paper on 11M crash dump analysis. Might be fun to be able to grok a little Macro-11 from time to time ... hmmm ... wonder if there's a Pro350, or even an old 11/44, languishing in someone's basement. ... "kenneth scharf" wrote in message ... Does anybody know where I can get a Harris or Intersil HD6100, HD6120, IM6100, or IM6120 microprocessor (cmos pdp-8)? I used to work for Digital, and thought it would be an interresting project to homebrew a PDP-8 system. I have a T11 microprocessor chip in the junbox someplace, so a PDP-11 system is also a possibility. |
"Dave, AA6YQ" wrote in message
news:lARab.522300$YN5.348403@sccrnsc01... No cheating! If you're going to homebrew a PDP-8, you have to build it out of discrete TTL. 73, Dave, AA6YQ Data General, 1972 - 1981 Designer of the Nova 2, Nova 3, MP200, and microEclipse CPUs, as well as some parts of FHP and EGO I thought FHP and EGO were completely separate, competing projects? (Admittedly, my only source is Kidder's book.) |
"Dave, AA6YQ" wrote in message
news:lARab.522300$YN5.348403@sccrnsc01... No cheating! If you're going to homebrew a PDP-8, you have to build it out of discrete TTL. 73, Dave, AA6YQ Data General, 1972 - 1981 Designer of the Nova 2, Nova 3, MP200, and microEclipse CPUs, as well as some parts of FHP and EGO I thought FHP and EGO were completely separate, competing projects? (Admittedly, my only source is Kidder's book.) |
alt.sys.pdp8
alt.sys.pdp11 alt.sys.pdp10 "xpyttl" wrote in message ... Talk about bad timing .... Just a couple of days ago two friends of mine hauled a PDP/8 out to the dump. Of course, you might not have been able to afford the power to run a REAL PDP/8. You do realize that there are people who collect these machines, and have been known to pay REAL MONEY for them, don't you??? |
alt.sys.pdp8
alt.sys.pdp11 alt.sys.pdp10 "xpyttl" wrote in message ... Talk about bad timing .... Just a couple of days ago two friends of mine hauled a PDP/8 out to the dump. Of course, you might not have been able to afford the power to run a REAL PDP/8. You do realize that there are people who collect these machines, and have been known to pay REAL MONEY for them, don't you??? |
"John R. Strohm" ) writes:
alt.sys.pdp8 alt.sys.pdp11 alt.sys.pdp10 "xpyttl" wrote in message ... Talk about bad timing .... Just a couple of days ago two friends of mine hauled a PDP/8 out to the dump. Of course, you might not have been able to afford the power to run a REAL PDP/8. You do realize that there are people who collect these machines, and have been known to pay REAL MONEY for them, don't you??? A friend sold a PDP/8 on Ebay for around $3000 US (and since he's in Canada, it will be even better for him), just in July. It did have some odd suffix (and some oddity about the hardware to go with it), so I'm not sure it that drove the price up. It was his first "home computer", and while he got a good deal on it (I forget the story, but I believe he bought it surplus in the seventies). He was moving, so it seemed like a good time to clear it out. Oddly, a couple of years ago I pointed him to someone periodically posting in buy and sell newsgroups looking for such computers. When my friend contacted him, the buyer was only willing to pay a few hundred dollars. Sort of to get it back to amateur radio, most people know that Wayne Green started BYTE, and then later Kilobaud. But in the November 1972 issue of 73 (the thickest up to that time), there was an article about building your own computer, from logic gates etc. It was not a construction article, but gave quite a bit of detail on what was needed for such a time and place. Nobody ever seems to mention that article after the fact. I'm still trying to decide if the article had any bearing on how things went later. Did Wayne print it because he saw things going in that way, or did he just print it as filler, yet when small computers came along a few years alter, it helped to direct him to small comptuers? Michael VE2BVW |
"John R. Strohm" ) writes:
alt.sys.pdp8 alt.sys.pdp11 alt.sys.pdp10 "xpyttl" wrote in message ... Talk about bad timing .... Just a couple of days ago two friends of mine hauled a PDP/8 out to the dump. Of course, you might not have been able to afford the power to run a REAL PDP/8. You do realize that there are people who collect these machines, and have been known to pay REAL MONEY for them, don't you??? A friend sold a PDP/8 on Ebay for around $3000 US (and since he's in Canada, it will be even better for him), just in July. It did have some odd suffix (and some oddity about the hardware to go with it), so I'm not sure it that drove the price up. It was his first "home computer", and while he got a good deal on it (I forget the story, but I believe he bought it surplus in the seventies). He was moving, so it seemed like a good time to clear it out. Oddly, a couple of years ago I pointed him to someone periodically posting in buy and sell newsgroups looking for such computers. When my friend contacted him, the buyer was only willing to pay a few hundred dollars. Sort of to get it back to amateur radio, most people know that Wayne Green started BYTE, and then later Kilobaud. But in the November 1972 issue of 73 (the thickest up to that time), there was an article about building your own computer, from logic gates etc. It was not a construction article, but gave quite a bit of detail on what was needed for such a time and place. Nobody ever seems to mention that article after the fact. I'm still trying to decide if the article had any bearing on how things went later. Did Wayne print it because he saw things going in that way, or did he just print it as filler, yet when small computers came along a few years alter, it helped to direct him to small comptuers? Michael VE2BVW |
"Michael Black" wrote in message
... "John R. Strohm" ) writes: You do realize that there are people who collect these machines, and have been known to pay REAL MONEY for them, don't you??? These guys had this thing to the dump before I even heard about it. To tell the truth, I'm not so sure I would have wanted to deal with posting it on eBay, packaging, shipping the beast, all that, even if I had a chance. Sort of to get it back to amateur radio, most people know that Wayne Green started BYTE, and then later Kilobaud. But in the November 1972 issue of 73 (the thickest up to that time), there was an article about building your own computer, from logic gates etc. Reminds me of something really great from a few years back. I was the advisor for an electronics specialty Explorer post (basically older Boy Scouts). Anyway, we were donated a PDP/4. This was an 18 bit machine, interfaced to the printer and tape with a 6 bit transcode instead of ASCII. Anyway, as we were first looking over the thing, with it's racks of cards and beautiful, huge electrolytics in the supply, my assistant advisor taps me on the shoulder and says "come look at this. See that rack of cards there? I think it's the accumulator." Sure enough, 18 cards for the accumulator, 18 cards for the program counter, 18 cards for the M register, one card per bit! ... |
"Michael Black" wrote in message
... "John R. Strohm" ) writes: You do realize that there are people who collect these machines, and have been known to pay REAL MONEY for them, don't you??? These guys had this thing to the dump before I even heard about it. To tell the truth, I'm not so sure I would have wanted to deal with posting it on eBay, packaging, shipping the beast, all that, even if I had a chance. Sort of to get it back to amateur radio, most people know that Wayne Green started BYTE, and then later Kilobaud. But in the November 1972 issue of 73 (the thickest up to that time), there was an article about building your own computer, from logic gates etc. Reminds me of something really great from a few years back. I was the advisor for an electronics specialty Explorer post (basically older Boy Scouts). Anyway, we were donated a PDP/4. This was an 18 bit machine, interfaced to the printer and tape with a 6 bit transcode instead of ASCII. Anyway, as we were first looking over the thing, with it's racks of cards and beautiful, huge electrolytics in the supply, my assistant advisor taps me on the shoulder and says "come look at this. See that rack of cards there? I think it's the accumulator." Sure enough, 18 cards for the accumulator, 18 cards for the program counter, 18 cards for the M register, one card per bit! ... |
Shortly after I began working at Tektronix, I recall seeing an official
desk name plaque sitting on top of a PDP-11. The name was "Petey P. Eleven". Roy Lewallen, W7EL |
Shortly after I began working at Tektronix, I recall seeing an official
desk name plaque sitting on top of a PDP-11. The name was "Petey P. Eleven". Roy Lewallen, W7EL |
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"xpyttl" wrote in message ... Talk about bad timing .... Just a couple of days ago two friends of mine hauled a PDP/8 out to the dump. Of course, you might not have been able to afford the power to run a REAL PDP/8. I never actually worked with an 8, although I did publish a paper on 11M crash dump analysis. Might be fun to be able to grok a little Macro-11 from time to time ... hmmm ... wonder if there's a Pro350, or even an old 11/44, languishing in someone's basement. .. "kenneth scharf" wrote in message ... Does anybody know where I can get a Harris or Intersil HD6100, HD6120, IM6100, or IM6120 microprocessor (cmos pdp-8)? I used to work for Digital, and thought it would be an interresting project to homebrew a PDP-8 system. I have a T11 microprocessor chip in the junbox someplace, so a PDP-11 system is also a possibility. Somewhere I have packed away a Sym-1 an Elf II and a Intersil 6100 familiarization board that had something like 256 bytes of ram, a boot rom and a uart (the uart is farkled either the data out or data in line is bad which is why I packed it away). I only have 25 more years till retirement, so I may find time then to pull them out then and see if they still work. As it is now I can't even find time to work on my remaining cp/m machines (Xerox 820IIHD, RS 4p, Balcones BNV205, Osborne 1, Osborne Exec, and Kaypro4). thanks, John. KC5DWD |
"xpyttl" wrote in message ... Talk about bad timing .... Just a couple of days ago two friends of mine hauled a PDP/8 out to the dump. Of course, you might not have been able to afford the power to run a REAL PDP/8. I never actually worked with an 8, although I did publish a paper on 11M crash dump analysis. Might be fun to be able to grok a little Macro-11 from time to time ... hmmm ... wonder if there's a Pro350, or even an old 11/44, languishing in someone's basement. .. "kenneth scharf" wrote in message ... Does anybody know where I can get a Harris or Intersil HD6100, HD6120, IM6100, or IM6120 microprocessor (cmos pdp-8)? I used to work for Digital, and thought it would be an interresting project to homebrew a PDP-8 system. I have a T11 microprocessor chip in the junbox someplace, so a PDP-11 system is also a possibility. Somewhere I have packed away a Sym-1 an Elf II and a Intersil 6100 familiarization board that had something like 256 bytes of ram, a boot rom and a uart (the uart is farkled either the data out or data in line is bad which is why I packed it away). I only have 25 more years till retirement, so I may find time then to pull them out then and see if they still work. As it is now I can't even find time to work on my remaining cp/m machines (Xerox 820IIHD, RS 4p, Balcones BNV205, Osborne 1, Osborne Exec, and Kaypro4). thanks, John. KC5DWD |
"xpyttl" wrote in message ... Talk about bad timing .... I never actually worked with an 8, although I did publish a paper on 11M crash dump analysis. Might be fun to be able to grok a little Macro-11 from time to time ... hmmm ... wonder if there's a Pro350, or even an old 11/44, languishing in someone's basement. .. "kenneth scharf" wrote in message ... Does anybody know where I can get a Harris or Intersil HD6100, HD6120, IM6100, or IM6120 microprocessor (cmos pdp-8)? I used to work for Digital, and thought it would be an interresting project to homebrew a PDP-8 system. I have a T11 microprocessor chip in the junbox someplace, so a PDP-11 system is also a possibility. I don't know if you would be interested, but there have to still be a few Heath LSI 11 systems out there. That was the only home version of the 11 that I know of. thanks, John. |
"xpyttl" wrote in message ... Talk about bad timing .... I never actually worked with an 8, although I did publish a paper on 11M crash dump analysis. Might be fun to be able to grok a little Macro-11 from time to time ... hmmm ... wonder if there's a Pro350, or even an old 11/44, languishing in someone's basement. .. "kenneth scharf" wrote in message ... Does anybody know where I can get a Harris or Intersil HD6100, HD6120, IM6100, or IM6120 microprocessor (cmos pdp-8)? I used to work for Digital, and thought it would be an interresting project to homebrew a PDP-8 system. I have a T11 microprocessor chip in the junbox someplace, so a PDP-11 system is also a possibility. I don't know if you would be interested, but there have to still be a few Heath LSI 11 systems out there. That was the only home version of the 11 that I know of. thanks, John. |
kenneth scharf wrote in message
... Does anybody know where I can get a Harris or Intersil HD6100, HD6120, IM6100, or IM6120 microprocessor (cmos pdp-8)? I used to work for Digital, and thought it would be an interresting project to homebrew a PDP-8 system. I have a T11 microprocessor chip in the junbox someplace, so a PDP-11 system is also a possibility. In fact, there is a fellow who sells kits and parts for the SBC6120, which is a build-your-own PDP-8 based on the IM6120 chip: http://www.sparetimegizmos.com/Hardware/SBC6120-2.htm And this fellow has an add-on for the SBC6120: http://www.jkearney.com/sbc6120/iob6120.htm Also, IM6100 chips show up on eBay from time to time. PDP-8 documentation may be found at Al Kossow's site: http://www.spies.com/~aek/pdf/dec/pdp8/ And at Dave Gesswein's site: http://www.pdp8.net Also, Bob Supnik's SIMH retrocomputing simulator supports the PDP-8. SIMH is hosted at Tom Shoppa's Trailing Edge site, currently down due to the effects of Isabel: http://simh.trailing-edge.com To those of you who chuckle at the OP's questions, I've got a PDP-8/A sitting about 5ft to my right as I type this, and a another in the basement, right next to a PDP-8/E, a VT78 (based on the IM6100) and a DECmate II (based on the IM6120). Just today I was at one place with a third PDP-8/A which I refurbished a few months ago, a working PDP-8/E, a PDP-8/L in need of serious help, 3 PDP-12s (essentially PDP-8/Is with added A/D and D/A I/Os), several DECmates and a LINC-8. Today I also stopped by a place with a several more DECmates and a PDP-8/L that I and a cohort rescued from the defunct United Electronics tube factory in Newark, NJ this past spring. PDP-8 Disease is incurable. Once infected you're happily chronic for life. You can do an awful lot on a computer with only 8 instructions that can directly address a mere 256 12-bit words at a time - if you're willing to think a little bit. PDP-8s are to computers what regens are to radios: Obsolete, but amazing for what they can do with so little, and a tremendous pile of fun to play with. In essence they're the spirit of QRP operation as applied to computers. Geoffrey G. Rochat Vice President, Rhode Island Computer Museum (www.osfn.org/ricm) Member, RetroComputing Society of Rhode Island (www.osfn.org/rcs) |
kenneth scharf wrote in message
... Does anybody know where I can get a Harris or Intersil HD6100, HD6120, IM6100, or IM6120 microprocessor (cmos pdp-8)? I used to work for Digital, and thought it would be an interresting project to homebrew a PDP-8 system. I have a T11 microprocessor chip in the junbox someplace, so a PDP-11 system is also a possibility. In fact, there is a fellow who sells kits and parts for the SBC6120, which is a build-your-own PDP-8 based on the IM6120 chip: http://www.sparetimegizmos.com/Hardware/SBC6120-2.htm And this fellow has an add-on for the SBC6120: http://www.jkearney.com/sbc6120/iob6120.htm Also, IM6100 chips show up on eBay from time to time. PDP-8 documentation may be found at Al Kossow's site: http://www.spies.com/~aek/pdf/dec/pdp8/ And at Dave Gesswein's site: http://www.pdp8.net Also, Bob Supnik's SIMH retrocomputing simulator supports the PDP-8. SIMH is hosted at Tom Shoppa's Trailing Edge site, currently down due to the effects of Isabel: http://simh.trailing-edge.com To those of you who chuckle at the OP's questions, I've got a PDP-8/A sitting about 5ft to my right as I type this, and a another in the basement, right next to a PDP-8/E, a VT78 (based on the IM6100) and a DECmate II (based on the IM6120). Just today I was at one place with a third PDP-8/A which I refurbished a few months ago, a working PDP-8/E, a PDP-8/L in need of serious help, 3 PDP-12s (essentially PDP-8/Is with added A/D and D/A I/Os), several DECmates and a LINC-8. Today I also stopped by a place with a several more DECmates and a PDP-8/L that I and a cohort rescued from the defunct United Electronics tube factory in Newark, NJ this past spring. PDP-8 Disease is incurable. Once infected you're happily chronic for life. You can do an awful lot on a computer with only 8 instructions that can directly address a mere 256 12-bit words at a time - if you're willing to think a little bit. PDP-8s are to computers what regens are to radios: Obsolete, but amazing for what they can do with so little, and a tremendous pile of fun to play with. In essence they're the spirit of QRP operation as applied to computers. Geoffrey G. Rochat Vice President, Rhode Island Computer Museum (www.osfn.org/ricm) Member, RetroComputing Society of Rhode Island (www.osfn.org/rcs) |
EGO was started by FHP engineers that declined to relocate, one of which was
me. The projects only became competitive after FHP moved to North Carolina and expanded its objectives. The book is accurate on this point, and pretty much everything else. 73, Dave, AA6YQ "John R. Strohm" wrote in message ... "Dave, AA6YQ" wrote in message news:lARab.522300$YN5.348403@sccrnsc01... No cheating! If you're going to homebrew a PDP-8, you have to build it out of discrete TTL. 73, Dave, AA6YQ Data General, 1972 - 1981 Designer of the Nova 2, Nova 3, MP200, and microEclipse CPUs, as well as some parts of FHP and EGO I thought FHP and EGO were completely separate, competing projects? (Admittedly, my only source is Kidder's book.) |
EGO was started by FHP engineers that declined to relocate, one of which was
me. The projects only became competitive after FHP moved to North Carolina and expanded its objectives. The book is accurate on this point, and pretty much everything else. 73, Dave, AA6YQ "John R. Strohm" wrote in message ... "Dave, AA6YQ" wrote in message news:lARab.522300$YN5.348403@sccrnsc01... No cheating! If you're going to homebrew a PDP-8, you have to build it out of discrete TTL. 73, Dave, AA6YQ Data General, 1972 - 1981 Designer of the Nova 2, Nova 3, MP200, and microEclipse CPUs, as well as some parts of FHP and EGO I thought FHP and EGO were completely separate, competing projects? (Admittedly, my only source is Kidder's book.) |
In the early/mid 60's the Science Club in my high school built a computer of
sorts out of salvaged telephone relays -- more of a binary adder than anything else (sorry, I was too interested in 20 meters at the time!). The Computer Museum is out in Mountain View California. Jack "Michael Black" wrote in message ... "John R. Strohm" ) writes: alt.sys.pdp8 alt.sys.pdp11 alt.sys.pdp10 "xpyttl" wrote in message ... Talk about bad timing .... Just a couple of days ago two friends of mine hauled a PDP/8 out to the dump. Of course, you might not have been able to afford the power to run a REAL PDP/8. You do realize that there are people who collect these machines, and have been known to pay REAL MONEY for them, don't you??? A friend sold a PDP/8 on Ebay for around $3000 US (and since he's in Canada, it will be even better for him), just in July. It did have some odd suffix (and some oddity about the hardware to go with it), so I'm not sure it that drove the price up. It was his first "home computer", and while he got a good deal on it (I forget the story, but I believe he bought it surplus in the seventies). He was moving, so it seemed like a good time to clear it out. Oddly, a couple of years ago I pointed him to someone periodically posting in buy and sell newsgroups looking for such computers. When my friend contacted him, the buyer was only willing to pay a few hundred dollars. Sort of to get it back to amateur radio, most people know that Wayne Green started BYTE, and then later Kilobaud. But in the November 1972 issue of 73 (the thickest up to that time), there was an article about building your own computer, from logic gates etc. It was not a construction article, but gave quite a bit of detail on what was needed for such a time and place. Nobody ever seems to mention that article after the fact. I'm still trying to decide if the article had any bearing on how things went later. Did Wayne print it because he saw things going in that way, or did he just print it as filler, yet when small computers came along a few years alter, it helped to direct him to small comptuers? Michael VE2BVW |
In the early/mid 60's the Science Club in my high school built a computer of
sorts out of salvaged telephone relays -- more of a binary adder than anything else (sorry, I was too interested in 20 meters at the time!). The Computer Museum is out in Mountain View California. Jack "Michael Black" wrote in message ... "John R. Strohm" ) writes: alt.sys.pdp8 alt.sys.pdp11 alt.sys.pdp10 "xpyttl" wrote in message ... Talk about bad timing .... Just a couple of days ago two friends of mine hauled a PDP/8 out to the dump. Of course, you might not have been able to afford the power to run a REAL PDP/8. You do realize that there are people who collect these machines, and have been known to pay REAL MONEY for them, don't you??? A friend sold a PDP/8 on Ebay for around $3000 US (and since he's in Canada, it will be even better for him), just in July. It did have some odd suffix (and some oddity about the hardware to go with it), so I'm not sure it that drove the price up. It was his first "home computer", and while he got a good deal on it (I forget the story, but I believe he bought it surplus in the seventies). He was moving, so it seemed like a good time to clear it out. Oddly, a couple of years ago I pointed him to someone periodically posting in buy and sell newsgroups looking for such computers. When my friend contacted him, the buyer was only willing to pay a few hundred dollars. Sort of to get it back to amateur radio, most people know that Wayne Green started BYTE, and then later Kilobaud. But in the November 1972 issue of 73 (the thickest up to that time), there was an article about building your own computer, from logic gates etc. It was not a construction article, but gave quite a bit of detail on what was needed for such a time and place. Nobody ever seems to mention that article after the fact. I'm still trying to decide if the article had any bearing on how things went later. Did Wayne print it because he saw things going in that way, or did he just print it as filler, yet when small computers came along a few years alter, it helped to direct him to small comptuers? Michael VE2BVW |
"Geoffrey G. Rochat" writes:
....[snip].... You can do an awful lot on a computer with only 8 instructions that can directly address a mere 256 12-bit words at a time - if you're willing to think a little bit. PDP-8s are to computers what regens are to radios: ....[snip].... You can also do an awful lot on a computer with only 8 instructions that can directly address only THIRTY-TWO NINE-bit words at a time: In 1969, while at Fairchild R&D Lab in Palo Alto, CA, I designed and built a 9-bit PDP-8 imitation (I called it "MINUS", since it was smaller than a mini-computer; if I had called it "MICRO", I might now be rich!) with 512 9-bit words of 200 nsec memory. Its instruction format used a: 3 bit opcode, 1 bit current page/page zero indicator, 1 bit indirect indicator, and a 4 bit address I also wrote a cross-assembler (in FORTRAN) for it, interfaced it to a 20Kbyte/second magnetic tape and a 3-foot x 5-foot flat bed plotter, and wrote a program (in MINUSASM) which, in a tight loop, read mag-tape printed-circuit wirelists produced on an IBM 360/44, buffered them in the upper half of memory, and then passed them to the plotter to draw large PC boards. Just before quiting time, we'd load a new mag tape, and 5-6 hours later another board had been drawn in three colors (horizontal, vertical, and vias). Ah, those were the heady days of youth! --Myron A. Calhoun. -- Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTX). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) |
"Geoffrey G. Rochat" writes:
....[snip].... You can do an awful lot on a computer with only 8 instructions that can directly address a mere 256 12-bit words at a time - if you're willing to think a little bit. PDP-8s are to computers what regens are to radios: ....[snip].... You can also do an awful lot on a computer with only 8 instructions that can directly address only THIRTY-TWO NINE-bit words at a time: In 1969, while at Fairchild R&D Lab in Palo Alto, CA, I designed and built a 9-bit PDP-8 imitation (I called it "MINUS", since it was smaller than a mini-computer; if I had called it "MICRO", I might now be rich!) with 512 9-bit words of 200 nsec memory. Its instruction format used a: 3 bit opcode, 1 bit current page/page zero indicator, 1 bit indirect indicator, and a 4 bit address I also wrote a cross-assembler (in FORTRAN) for it, interfaced it to a 20Kbyte/second magnetic tape and a 3-foot x 5-foot flat bed plotter, and wrote a program (in MINUSASM) which, in a tight loop, read mag-tape printed-circuit wirelists produced on an IBM 360/44, buffered them in the upper half of memory, and then passed them to the plotter to draw large PC boards. Just before quiting time, we'd load a new mag tape, and 5-6 hours later another board had been drawn in three colors (horizontal, vertical, and vias). Ah, those were the heady days of youth! --Myron A. Calhoun. -- Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTX). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) |
....[snip]....
The Computer Museum is out in Mountain View, California. There's another Computer Museum in Bozeman, Montana. It's not nearly as big, but it contains nice stuff. --Myron. -- Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTX). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) |
....[snip]....
The Computer Museum is out in Mountain View, California. There's another Computer Museum in Bozeman, Montana. It's not nearly as big, but it contains nice stuff. --Myron. -- Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTX). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) |
"Dave, AA6YQ" wrote in message news:lARab.522300$YN5.348403@sccrnsc01... No cheating! If you're going to homebrew a PDP-8, you have to build it out of discrete TTL. I had my PDP-8S work-alike operational about 30 years ago. I built it from TTL. |
"Dave, AA6YQ" wrote in message news:lARab.522300$YN5.348403@sccrnsc01... No cheating! If you're going to homebrew a PDP-8, you have to build it out of discrete TTL. I had my PDP-8S work-alike operational about 30 years ago. I built it from TTL. |
"xpyttl" wrote in message ... Anyway, as we were first looking over the thing, with it's racks of cards and beautiful, huge electrolytics in the supply, my assistant advisor taps me on the shoulder and says "come look at this. See that rack of cards there? I think it's the accumulator." Sure enough, 18 cards for the accumulator, 18 cards for the program counter, 18 cards for the M register, one card per bit! I built my home-brew PDP-8 in a bit-slice way. Each of the main cards had one bit of the accumulator, memory data register, memory address register and the "other" register - 12 cards for the main data paths. As an ancient aside, the "first minicomputer" Whirlwind at MIT was a 16-bit bit slice machine. There was one whole 6-ft rack for each slice. Thus the main part of the machine took 16 racks. I never saw the beast, but we (at USAF Cambridge Research Labs) did do an experiment or two with it driving our ground to air digital data link. That was in 1953, IIRC. But I was VERY young back then..... 73 de bob w3otc |
"xpyttl" wrote in message ... Anyway, as we were first looking over the thing, with it's racks of cards and beautiful, huge electrolytics in the supply, my assistant advisor taps me on the shoulder and says "come look at this. See that rack of cards there? I think it's the accumulator." Sure enough, 18 cards for the accumulator, 18 cards for the program counter, 18 cards for the M register, one card per bit! I built my home-brew PDP-8 in a bit-slice way. Each of the main cards had one bit of the accumulator, memory data register, memory address register and the "other" register - 12 cards for the main data paths. As an ancient aside, the "first minicomputer" Whirlwind at MIT was a 16-bit bit slice machine. There was one whole 6-ft rack for each slice. Thus the main part of the machine took 16 racks. I never saw the beast, but we (at USAF Cambridge Research Labs) did do an experiment or two with it driving our ground to air digital data link. That was in 1953, IIRC. But I was VERY young back then..... 73 de bob w3otc |
My first CPU, designed and built as a lab project in 1971, used 16-bit
registers and memory words, but the data paths were 1-bit serial. The memory was implemented with a ~9ms acoustic delay line, in which 8192 recirculating bits were stored. One of the neat aspects of this design is that one could continuously view all of memory with a single scope probe! It was unique in its use of a then-newfangled touchtone keypad for entering hexadecimal values into registers, replacing the individual toggle switches customarily used for that purpose. To prove its completion, we programmed it to perform BCD division; after literally seconds of flashing the lights attached to its registers, it halted with the correct result ablaze and the TA intoned "it lives". It was a defining moment... 73, Dave, AA6YQ wrote in message ... "Geoffrey G. Rochat" writes: ....[snip].... You can do an awful lot on a computer with only 8 instructions that can directly address a mere 256 12-bit words at a time - if you're willing to think a little bit. PDP-8s are to computers what regens are to radios: ....[snip].... You can also do an awful lot on a computer with only 8 instructions that can directly address only THIRTY-TWO NINE-bit words at a time: In 1969, while at Fairchild R&D Lab in Palo Alto, CA, I designed and built a 9-bit PDP-8 imitation (I called it "MINUS", since it was smaller than a mini-computer; if I had called it "MICRO", I might now be rich!) with 512 9-bit words of 200 nsec memory. Its instruction format used a: 3 bit opcode, 1 bit current page/page zero indicator, 1 bit indirect indicator, and a 4 bit address I also wrote a cross-assembler (in FORTRAN) for it, interfaced it to a 20Kbyte/second magnetic tape and a 3-foot x 5-foot flat bed plotter, and wrote a program (in MINUSASM) which, in a tight loop, read mag-tape printed-circuit wirelists produced on an IBM 360/44, buffered them in the upper half of memory, and then passed them to the plotter to draw large PC boards. Just before quiting time, we'd load a new mag tape, and 5-6 hours later another board had been drawn in three colors (horizontal, vertical, and vias). Ah, those were the heady days of youth! --Myron A. Calhoun. -- Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTX). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) |
My first CPU, designed and built as a lab project in 1971, used 16-bit
registers and memory words, but the data paths were 1-bit serial. The memory was implemented with a ~9ms acoustic delay line, in which 8192 recirculating bits were stored. One of the neat aspects of this design is that one could continuously view all of memory with a single scope probe! It was unique in its use of a then-newfangled touchtone keypad for entering hexadecimal values into registers, replacing the individual toggle switches customarily used for that purpose. To prove its completion, we programmed it to perform BCD division; after literally seconds of flashing the lights attached to its registers, it halted with the correct result ablaze and the TA intoned "it lives". It was a defining moment... 73, Dave, AA6YQ wrote in message ... "Geoffrey G. Rochat" writes: ....[snip].... You can do an awful lot on a computer with only 8 instructions that can directly address a mere 256 12-bit words at a time - if you're willing to think a little bit. PDP-8s are to computers what regens are to radios: ....[snip].... You can also do an awful lot on a computer with only 8 instructions that can directly address only THIRTY-TWO NINE-bit words at a time: In 1969, while at Fairchild R&D Lab in Palo Alto, CA, I designed and built a 9-bit PDP-8 imitation (I called it "MINUS", since it was smaller than a mini-computer; if I had called it "MICRO", I might now be rich!) with 512 9-bit words of 200 nsec memory. Its instruction format used a: 3 bit opcode, 1 bit current page/page zero indicator, 1 bit indirect indicator, and a 4 bit address I also wrote a cross-assembler (in FORTRAN) for it, interfaced it to a 20Kbyte/second magnetic tape and a 3-foot x 5-foot flat bed plotter, and wrote a program (in MINUSASM) which, in a tight loop, read mag-tape printed-circuit wirelists produced on an IBM 360/44, buffered them in the upper half of memory, and then passed them to the plotter to draw large PC boards. Just before quiting time, we'd load a new mag tape, and 5-6 hours later another board had been drawn in three colors (horizontal, vertical, and vias). Ah, those were the heady days of youth! --Myron A. Calhoun. -- Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTX). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) |
Very cool. What did you use for memory?
73, Dave, AA6YQ "R J Carpenter" wrote in message ... "Dave, AA6YQ" wrote in message news:lARab.522300$YN5.348403@sccrnsc01... No cheating! If you're going to homebrew a PDP-8, you have to build it out of discrete TTL. I had my PDP-8S work-alike operational about 30 years ago. I built it from TTL. |
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