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Still More Front Panels

On the first page, this illustration showed what the front panel of the STRETCH computer looked like:

That illustration was based on the colorful front panel of the first STRETCH shipped to Los Alamos. Most of the STRETCH computers that were delivered to customers had a front panel slightly different in component layout (note the bottom right corner),

and very different in color scheme.

On the first page, illustrations show the front panels of two of the largest models in the System/360 series, the model 75 and the model 195. This illustration shows what the front panel of a more typical model, the Model 40, looks like:

I had wanted to illustrate the front panel from one of the large Univac computers, such as the 1107, 1108, or 1110, to show that IBM was not the only company that made computers with impressive front panels; it was difficult for me to find a sufficiently detailed picture of the front panel of one of their computers, until I found one for another of their machines, the Univac 9400:

The styling of this front panel is similar to that of the panel for the Univac 1108. For that matter, the Omega 480 computer, sold through Control Data, clearly had a Univac-style front panel, and may have been a rebranded Series/90 machine, as the Univac machines based on the Spectra 70 were known.

The Univac 9400 has an interesting history as being, very nearly, a legend shrouded in mystery. It is well known that RCA made a line of computers largely compatible with the IBM 360, known as the Spectra 70 series of computers. This product line was eventually purchased by Remington Rand in September 1971. But prior to this purchase, Univac had made the 9200 and 9300 computers, successors to the Univac 1050, which were sold both as stand-alone small-scale computers and as peripheral controllers for larger Univac systems. They were compatible with a member of the IBM System/360 family, the Model 20. The Model 20 did not support floating-point arithmetic, or even 32-bit integer arithmetic, and it used only registers 8 through 15 as base registers, so that it had an addressing mode in which its memory could be referenced without the use of base registers, which were not really required due to the memory limitations of that model.

Included among the systems for which a 9300 was offered as a peripheral was the Univac 418-III. This was a computer with an 18-bit word designed for real-time use. Initially, it seemed bizarre to me that one would attach a mainframe as a peripheral to a minicomputer; but since the 9300 was similar to a Model 20, it really was, even in that case, a smaller computer than the one which it served as a peripheral; and the 418-III was large for a computer with 18-bit instructions; for example, hardware floating point was available for it.

At Univac, work had been in progress on a more powerful machine, the Univac 9700, prior to the purchase of the Spectra 70 line from RCA; I have read that this work was put to use in a subsequent Series 90 computer from Univac, after modifications were made to achieve full Spectra 70 compatibility. The Univac 9700 was to have been, like the Univac 9400 before it, compatible with the other members of the System/360 family to an extent. However, I have learned that the Univac 9400 did not support the BXLE instruction, a problem state instruction used for looping in the IBM System/360, so contrary to my initial impression, the 9400 was actually less compatible with the System/360 than a Spectra 70 was. Also, some Univac 9700 computers were, in fact, manufactured and sold, again contrary to my initial impression.

The maximum memory size of a Univac 9400 was 128 kilobytes, which implies it was somewhere between an IBM System/360 Model 30 (maximum 64 kilobytes) and an IBM System/360 Model 40 (maximum 256 kilobytes), but it may also have had paging hardware like that of the much larger IBM System/360 Model 67, this being discussed on an internal memorandum about a proposed Univac 9500.


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