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RCA Spectra 70 Series

M

mpatoray

Experienced Member
Joined
Oct 19, 2005
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76
Location
New Middletown Ohio
Hello,

I was reading about the RCA Spectra 70 series of computers. They seem like rather neat boxes with interesting early usage of IC's at a time when Germanium transistors where the norm.

Does anyone know of museums or collectors who have any of these systems?

Does anyone have war stores from working on them?

Thanks,

Matt
 
Germanium? The Spectrolas were introduced after the S/360 and used some of the first (RCA-manufactured) integrated circuits. Silicon ruled supreme then.

Maybe no original RCA-branded operating hardware, but they were also rebadged by Siemens and English Electric. Eventually morphed into the Univac 9000 line--there shouldn't be much of a problem finding examples of those.

Notable for me in that they were one of the easier mainframes of the period to microprogram.
 
I can never decide if the Spectra series, which were also made and sold in the UK by English Electric and later ICL as System/4 were a great idea or a half fudged clone of System/360.

On the plus side the interrupt processing was much faster, but that meant you couldn't run any IBM systems software. I can't see any reference to the system calls so I have no idea if IBM applications were usable or if they still needed to be re-compiled to run...
 
If memory serves (and it increasingly doesn't nowadays), the resident internals of the OS were different, but instruction-wise, user applications were the same. If you reported to RCA instead of IBM after a hard night, it might take you until your second cup of coffee to figure out that you weren't in Poughkeepsie any more. Compare the Spectrola's TDOS with S/360 DOS JCL, you might not notice. Assmbler mnemonics where identical as far as the user was concerned--you started your program the same way--BALR x,0, USING *,x and ended it with a SVC (or a macro to generated one).

Given the differences between other manufacturer's machines and IBM's, RCA was pretty darned close.

(FWIW, the popular nickname "Spectrola" dates from the time when the Radio Corporation of America (RCA) purchased the Victor Talking Machine Company (the US branch only; other countries had their own versions, so "JVC" = Japan Victor Company) and was for some time, known as "RCA Victor"--and the merged company for a time held onto the trade name "Victrola" for their record players.)
 
Took a look at a brochure for the /45. It appears that you could order the IBM emulation for a number of systems with your Spectra. Not an expert but yes I agree clearly RCA marketed their Spectras as capable of IBM emulation among other things. They also talked up the hardware speed and microcircuitry as well.
 
Have you a link to that. I can see several manuals on Bitsavers but not that one!. I notice the other dig at IBM in the sales brochure, where it says you won't get bogged down by the OS!.
 
I just came across this thread. I worked for RCA back in the '70s' as a field service tech (they called us 'CSRs'). There was an experimental version of a hypervisor running at one client's installation that would load OS/360 as a virtual application. It would report "Model not supported" after start-up, but then would operate normally. I don't think it ever went into production, though.
 
Chuck(G) said:
Germanium? The Spectrolas were introduced after the S/360 and used some of the first (RCA-manufactured) integrated circuits. Silicon ruled supreme then.
Click to expand...

But no Magic Brain.

Magic-Brain-small.png
 
My recollection is that the Spectrolas were probably the most early S/360-type machines for do-it-yourself microprogramming. I remember a red book that talked about rolling your own on the RCA machines and the S/360 Model 30.
 
Frank, I too was a CSR. i maintained Spectra 70-25,35 in our location in Mid USA.

Frank, I too was a CSR. i maintained Spectra 70-25,35 in our location in Mid USA.

frankt said:
I just came across this thread. I worked for RCA back in the '70s' as a field service tech (they called us 'CSRs'). There was an experimental version of a hypervisor running at one client's installation that would load OS/360 as a virtual application. It would report "Model not supported" after start-up, but then would operate normally. I don't think it ever went into production, though.
Click to expand...

Frank do you have any idea where I could get my hands on a copy of the schematics for the Spectra 70-15/25? I have need of them and did not keep mine from that time period of my career.

Thanks
Lane_S
 
Lane_S said:
Frank do you have any idea where I could get my hands on a copy of the schematics for the Spectra 70-15/25? I have need of them and did not keep mine from that time period of my career.

Thanks
Lane_S
Click to expand...

Sorry Lane, but all my old docs were lost over the years. Have you tried BitSavers?
 
I realize this is an old tread, but, I'd like to add to it.. I worked at Palm Beach Gardens on the Spectra 70 series till RCA closed the computer division in early 70's. The Spectra 70 was on many side-by-side trials with the IBM 360. My recollection is the Spectra 70 did better or equal to IBM, but we generally lost the contract because IBM was better known.
We sold Spectra 70 (rebranded) through Siemens in Germany and some through Hitachi in Japan. We had Germany engineers from Siemens always at the PBG facility While I was there. And, I remember that we sent one of our card readers to japan and in a few months I was asked to help evaluate an example of a duplicate they had built. Mechanically, it was identical to ours, but all the circuit boards had been redesigned. It worked well. I don't know why they chose to redesign them other than for nomenclature and marking reasons.
 
Interesting. Do you have any recollections of the Spectra 70/752 Video Data Terminal? Those RCA engineers were pretty clever to coax ASCII out of a mechanical Selectric keyboard.

I have a long-running project building a replica of that keyboard, machining and 3D printing new versions of the RCA parts (as I interpret them) as well as modifying IBM parts where I can.
 
It might look like a crappy 1960s terminal but to me it's one of the most interesting ever built: it appeared at a time where four technologies old and new intersected: it incorporates moving mechanical parts, a valve (tube), discrete transistors and early ICs all in the one unit.

In the above photo you can see the keyboard enclosure has a lot of space to the right and top of the keyboard keys, this is where the AC synchronous motor is, underneath the function keys/nomenclature plate. I have a 110 volt IBM motor from the 60s my dad must have brought home, virtually identical to the RCA one. Its pinion matches a modified IBM spring clutch which is now fitted to the filter shaft so it is driven directly rather than in the whole Selectric where the op shaft drives the print shaft and filter shaft. Still some motor work to do so currently I use a speed-controlled LEGO motor with 3D printed gears as the temporary filter shaft drive. I installed an addtional interposer for bit 7 and filed the latch for it from a scrap of sheet metal. Each latch interposer also has a return spring as there is no Whippletree in the power frame to supply tension. There are many mechanical modifications done and still a lot to do but it's getting there.
 
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Not sure if this is actually a post. I found a link to the Spectra 70/46 Reference Manual. A quality scan at that. Not wanting to violate any rules here, lemme know if it's of interest and I will either post or link to the site.
 
mpatoray said:
Hello,

I was reading about the RCA Spectra 70 series of computers. They seem like rather neat boxes with interesting early usage of IC's at a time when Germanium transistors where the norm.

Does anyone know of museums or collectors who have any of these systems?
Click to expand...
time for a ten year necro-reply
CHM has one

System 4004 console | 102668108 | Computer History Museum

www.computerhistory.org www.computerhistory.org

scanning the documentation and reading the tapes would be a nightmare
 
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