The Web Site to Remember National Semiconductor's Series 32000 Family


Symmetric Computer Systems was funded by William Jolitz in 1982 in California/US. A website is available that tells more details: Story of SCS.

Symmetric 375

The Symmetric 375 was packaged in a nice case with a scope-type handle for carrying. It is said that the number 375 was chosen to show that the system has half the performance of a VAX11/750. But I doubt that this is true because the speed of the two systems should be roughly the same.

The system was built around the NS32016 CPU running at 10 MHz. It used the FPU and the MMU. Main memory was 2 Mbytes, no wait states and no parity protection. Hard drive was 50 MByte minimum. The system software was a sort of Berkeley 4.2 . The price of the basic version was around $5000. Upgrades were available, for example a bigger hard disk drive. For $4000 more Ethernet hardware was included.

The system shown here is owned by Bernd K. Thank's to him for the photos.

Fig. 1. The front side of the Symmetric 375 system.

Fig. 2. The rear side of the Symmetric 375 system.

Fig. 3. A look inside shows that the system seems to be made of two boards (This photo is not made by Bernd).

Fig. 4. The power supply and the hard disk drive of the Symmetric 375 system.

Fig. 5. This compute board uses heat sinks on the Series 32000 parts and on some other chips.

The heat sinks shown in Figure 5 are obviously needed because the Series 32000 chip set is overclocked. The quartz has a frequency of 22.118 MHz which will result in a system clock of 11.059 MHz. 22.118 MHz is used to generate baud rates because it is 9 * 128 * 19,200 Bauds.

Was the system already delivered with the faster frequency or did a user this upgrade?

The two SCN2681A are dual channel asynchronous receiver/transmitter devices. The WFJ on the PCB stands for William Jolitz.

Fig. 6. The board looks like a separate I/O board. But it is the electronic board of the hard disk drive.

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