SPARCstation 20

The SPARCstation 20 (a.k.a. SS20, codename Kodiak) is a discontinued Sun Microsystems workstation based on the SuperSPARC or hyperSPARC CPU. It is the last model in the SPARCstation family of Sun "pizza box" computers, which was superseded by the UltraSPARC design in 1995.

The SPARCstation 20 has dual 50 MHz MBus ports that allow it to use faster CPUs than the SPARCstation 10. With two dual-CPU modules and updated firmware, the SPARCstation 20 supports a maximum of 4 CPUs. The fastest CPU produced for the SPARCstation 20 is the 200 MHz Ross hyperSPARC.

The PROM in the SPARCstation 20 determines CPU compatibility. Version 2.25r is the last PROM release for the SPARCstation 20.

The SPARCstation 20 has 8 200-pin DSIMM slots, and supports a maximum of 512 MB of memory with 64 MB modules. Memory modules for the SPARCstation 20 are compatible with the SPARCstation 10, Sun Ultra 1, and some other computers in the sun4m and sun4u families, but they are physically incompatible with the SIMM slots found in PC computers.

2 of the 8 SIMM slots are wider than the others and can be used with non-memory peripherals like caching NVSIMM and video VSIMM cards.

The SPARCstation 20 has two internal SCA bays, an external SCSI connector, and two bays for CD-ROM or floppy drives. Earlier revisions of the SPARCstation20 case contain a CD-ROM and floppy bays that are slightly shorter than a standard 3.5" bay and regular devices intended for PC compatible computers do not usually fit. Later revisions of the SPARCstation20 and SPARCstation5 have a narrower slot for the floppy drive so a more-standard CD-ROM can fit.

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