Computer History: RCA - A Brief Look at the RCA 501 Transistorized Computer (Radio, Electronics)

For review and discussion, we took at RCA's early computers, including the RCA 501. After three years of development, RCA introduced the all-transistor RCA 501, a medium- to large-scale computer, advertised as "the world's most advanced electronic data processing system." Rare vintage photos and film footage from 1950's shows master control console, printed circuit boards, core memory, tape drives and more. RCA (Radio Corporation of America) was a major American radio, TV and electronics corporation which also produced large scale computers until it sold its computer division to Sperry (UNIVAC) in 1971. See also THE RCA BIZMAC, world's largest commercial computer

Video provided for educational and historical use only, by the Computer History Archives Project (CHAP).

[itominack]

Wow ! Thanks for posting this ! I was part of a 2-man team that ran an RCA 501 for the Navy in the early 1970s. We recorded and processed ballistics test data for numerous rocket motors (both production and experimental units). It was extremely large, and somewhat temperamental at times, but it worked extremely well. For ALL that size, we only had 64k of RAM. In its day, it was a performer.

[hollydog]

Pittsburgh, 1969. Just got out of USAF. Worked on the 501 for two years. We use to write a test program that would result in all of the button flashing on and off. Then we would turn off the room lite's and watch the light show. Looked like the Starship Enterprise.

[BertGrink]

Interesting to see how those slot-in cards had small daughter boards each supporting one transistor and a few passive components.

[jamesslick]

So sad that so MANY great American companies are either gone all together, or are just "Brand Licenses". Silly Story: One time I was REALLY HIGH (weed) and was just blabbing into my tape recorder (a Wollensak, no less!) One of the things I said on there was "I believe that I have reached my Zenith!!...It's right next to my RCA!" (I still have a cassette and now digitized copy of that tape!) Today hardly anyone would "get" that line. (it wouldn't work with Vizio and TCL) :(

[ladsongeddings]

Worked for RCA Computer Division at Palm Beach Gardens, Palo Alto, and Cinnaminson; mostly assembly language Spectra 70 executive programming (operating systems). It was a good respected division of the company to work for and they were very good to their employees. Many thought the decision to sell the division at the time was the result of board room politics because audits done after the sale proved the division to be profitable.

[lowercherty]

The iron ore plant I worked at had a Spectra 70 system doing process control in the mid 70's. When the plant was expanded in 1979, the new section had a Honeywell system that looked and acted very similarly. This was all home written software that was way ahead of it's time, predating commercial DCS systems. It worked well and was very reliable.

[dalecomer]

All that button action on the control console is nutty. They needed a human factors design consultant.

[henrye.binger]

Way back in high school, I was writing BASIC programs, punching paper tape on a Teletype terminal that dialed into an RCA Spectra 70 time-sharing system at the Houston school district's Media Center. That was in 1970, and I've written a LOT of code since then.

[warrenfrank]

Surprised that it was not mentioned that RCA was a pioneer in integrated circuits. The RCA 1802 microprocessor, also known as the COSMAC CDP 1802, was used in many satellites built in the 1970s and through the 1980s. Radiation hardened versions of the 1802 were manufactured under license agreements with RCA. Civilian space projects like he Hubble space telescope and the Magellan probe used the 1802 microprocessors. Military satellites like GEOSAT and MAGSAT also used of this part. It when the 1750A parts were available, 1802 parts were no longer used.

[tommybewick]

Stil shocking to me even all these years later one of the biggest and best American electronics companies went out of business, such a shame. Thanks for sharing this well done history.

[johneygd]

Mind blowing technology and it's name will live on in the hearth's of fans.

[josephcote]

I learned COBOL on an RCA Spectra 70-45F.

[david]

The quick view of the magnetic tape unit in operation showed a very primitive tensioning system that oscillated, alternately leaving the tape loose and tightening it. This would undoubtedly have resulted in very short tape lifetime, as the fatigue induced in the plastic tape would have probably often broken them. It would be interesting to find out if this actually happened.

The Univac and other computers of the late 1950s used sophisticated vacuum sensing to detect the position of the tape loops and to keep the tape loops in range. In other words, the tape loops provided high-speed access to a few inches of tape, so that the tape could be accelerated and decelerated very quickly, prior to any motion of the tape reels being necessary.

[randaldavis]

I got to operate a RCA 301 in 1981, 1 & 2 (backup computer) of 3(?) that were still running in the country. 125bpi magnetic tapes, printer (that was lucky to print characters in a straight line) and a 800bpi ibm tape drive for making a tape to input into the IBM mainframes. the RCA system collected job labor data from each process preformed on parts.

[unbiased]

So, that's what the world's most advanced electronic data processing system looks like! 2:52

[JamesJones-ztyx]

Wow. In 1972 I went to a vo-tech school in Oklahoma City. They started us on IBM unit record machines, but then we got to use the RCA 301 they had. I wrote a program to multiply two numbers (BCD, of course). The addressing modes were so limited that I ended up writing self-modifying code to get the partial products lined up right to add up. Punched it on cards in machine code.... this is the point where I say "Get off my lawn", right?

[SouthwesternEagle]

That 501 control panel has more buttons than anything I have ever seen, including aircraft!

[pdxrailtransit]

Very interesting. Being on the IBM Blue side of things was not aware that RCA did D.P.

[Jeffrey]

3:05 Is this real? Most of these buttons on this keyboard & panel have no markings on them, just pretty primary colors..

[brettknoss]

If RCA could have got someone like Bally Manufacturing, and pivoted there computer division towards consumer game machines, and there mainframes to specialize in polling and bookmaking.