I am confident of most of the following information except oddly the manufacturer. I think that it was NCR but I am not quite sure. I have no idea of the model.

The machine had 32k of memory but 24 bit words not bytes. "Byte" was not yet in my vocabulary. Mostly, these words stored numbers: integers in 2's complement or floats. When characters were stored, they used a 6 bit code and were packed 4 to a word. Obviously, the coding was not ASCII, "ASCII" was also not yet in my vocabulary. There was no room for upper and lower case so it was usual to work entirely in upper case. If you insisted on lower case then you needed to use shift characters. Space was coded as 0. When I discovered ASCII later, I was surprised that space was 32, 0 had come to seem the natural code for space.

One reason that I am confident of this is that the number 2^23 = 8388608 is still burned into my brain as 8388607 was the maximum positive integer.

No hard disk and it was quite a while before I learned to use the tape drives.

The system accepted a few simple control commands. A typical program looked like this:


Loads of ugly code with GOTOs and stuff




FORTRAN was the most commonly used language but COBOL, ALGOL, and an assembly language called NEAT (I think) were also available.

So, can anyone confirm that it was a NCR or correct me?

Would anyone be able to guess the model?

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    My first experience of computing was at school in 1974. I joined a very small computing club: one teacher and two other members. We did not ever see the computer, it was 20 miles away in a technical college. We wrote our programs in pencil on paper forms, a secretary typed them onto paper tape, submitted them via modem to her husband who worked in the technical college. He ran them and brought the large green and white stripy perforated output home. The secretary would bring the print out to school the next day. So, a 24 hour turn around for compiles. – badjohn Jan 27 '18 at 10:53
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    I removed some more anecdotal text. After a while we overtook the teacher. An exciting point was when we discovered other languages. There was COBOL but that soon bored us. I found and liked ALGOL but the others did not. I liked the block structure. Finally we discovered the assembler. The assembly language was called NEAT (I think). We felt this was real programming. High level languages were for wimps. – badjohn Jan 27 '18 at 10:57
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    @tofro This was in the UK but it was not necessarily a UK machine. It may have been from the US. Oddly, I never saw it (see the anecdote in one of my earlier comments). – badjohn Jan 27 '18 at 11:03
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    You might want to have a borwse here and find if something rings a bell on old NCR computers: thecorememory.com/html/memory_dumps.html – tofro Jan 27 '18 at 11:21
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    @tofro That seems to confirm that it was an NCR. The NEAT language is quite familiar. I had forgotten the ADD / ADDN instruction pairs but it comes back now. I don't recognise the model. Some talk of bytes and ASCII and hence are too new. The era is correct but the machine that I was using might have been old even at the time. I don't expect that the technical college bought it new. It was probably second hand or even a cast off. – badjohn Jan 27 '18 at 11:50

Was it an Elliot-Automation 41xx system, an actual 24-bit contemporary of the 315 also sold by NCR during the mid-60s?

I came across one of these mentioned as a 32K word 24-bit system:

I started on an ICL 4120, which was upgraded to an Elliott 4130 (yes, the 40130 was made first, they were just at the time ICL for formed from Elliott and the others), the 4120 with rin core and the 4130 with plated wire storage (32K of 24 bit words!)

The Wikipedia page for Elliot Brothers (computer company) lists:

  • Elliott 4100 series (1966) A joint development with NCR Corporation. Elliott selling to the scientific market and NCR selling to the commercial market.

Assorted references mention NEAT in association with this series of systems.

In fact, Barbosa (1977, 2016) had collaborated with the engineer Azevedo Machado in the coding of extensive source codes in FORTRAN, ALGOL, and NEAT in an NCR/Elliot 4130 [...]

(The Bloomsbury Handbook of Electronic Literature, 2017)

However, I've seen at least three different expansions for NEAT in association with NCR, so perhaps it shouldn't be taken as a reference to a single coherent language or technology.

It seems the 41xx line did not initially have a COBOL compiler, but eventually had one by the time it became part of ICL.

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    Yes, I am pretty sure that is it. I remember some confusion over whether it was an NCR or ICL. (Remember that I never saw it.) I tended to assume NCR due to the presence of Neat. Further evidence of the correctness is that I recognise one of the names in that newsgroup as a former classmate. – badjohn May 16 '18 at 9:41

Definitely a 4130, I spent five years of my life maintaining these as well as coding in machine code. A 24 bit machine with a built in floating point unit and no chips only transistors running on a 10v supply. Happy days?!


Definitely looks like a 4100 series. I worked for NCR as a mainframe computer operator (NCR 315), then as a technical writer writing manuals for the NCR Elliott 4100 series, then in the Marylebone head office in Programming Information Services (with the unfortunate acronym of P.I.S.) where I was responsible for writing the operating system drivers that allowed the 4100 series to use NCR Card Random Access Memory devices ("CRAM").

Hope that helps. (And yeah, I'm still actively cutting code.) :)

  • Thanks for the additional confirmation. The accepted answer seems fairly certain. It was pretty certainly an ICL 4120 later upgraded to a 4130. – badjohn Mar 27 '20 at 11:22

Was it the NCR 315?

It used 12-bit slab memory structure using core memory. The instructions could use a memory slab as either two 6-bit alphanumeric characters or as three 4-bit BCD characters. Basic memory was 5000 "slabs" of handmade core memory, which was expandable to a maximum of 40,000 slabs in four refrigerator-size cabinets.


A numeric value contains up to eight slabs.

So it supports numeric operations on words in multiples of 12 bits, up to 96 bits.

Available Languages

  • NCR Assembler Language

  • National Electronic Autocoding Technique (NEAT)


  • BEST

Hmm, Fortran and Algol are missing from that list. Maybe you are thinking of a successor that inherited the NCR 315's 12-bit words?

Edit: Sorry, I didn't read the comments before posting this or I would have seen the suggestion that it might be the 315 or the 615. I guess great minds think alike!

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    The 315 seems to be a close miss unless I am wrong about the 24 bit words. I see some references to a 615 but little detail. It was released in 1968 so it is plausible that the technical college had a second hand one in 1974. There is mention of a hard disk. We did not have one initially but one was added just before I left the school. So the system was capable of using one. thocp.net/companies/ncr/ncr_company.htm – badjohn Jan 27 '18 at 15:54
  • @badjohn I've added the part where a numeric value can contain multiple slabs, so 24-bit numeric operations are supported. But the machine doesn't seem to support Fortran or Algol, so again it's a miss. :-/ – snips-n-snails Jan 27 '18 at 17:10
  • Thanks. There is no doubt about the Fortran, It was the first language that I used and I still have some paper tape and program listings somewhere. – badjohn Jan 27 '18 at 17:24

I programmed NCR Century computers (the 615 series) from 1973. These were 8 bit bytes, in 16 byte words. Each byte held 1 Ascii character, or 2 digits 0-9. "Byte" was invented in 1956 (when I was 7!). Burroughs B3500's used 8 bit bytes and Ascii, as did IBM, who used EBCDIC code. Holding text in 6 bits, in 24 bit words was how the ICL 1900 series worked.


This is a reach, but how about an SDS 930?

It had 24 bit words and ALGOL. Don't know about the rest of it.

  • Thanks. The manufacturer seems to be now certainly NCR due to the presence of NEAT. Just the model remains to be identified. – badjohn Jan 28 '18 at 12:21

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