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APPENDIX
B
Functional Description
This chapter describes the system architecture for the SPARCstation 20.
See Chapter 1 for illustrations of the back panel.
System Overview
The SPARCstation 20 supports a system board, a power supply, up to two hard disk
drives, a SunCD 2Plus or a SunCD 4 drive, and a diskette drive. A variety of SBus
cards and MBus modules can be installed on the system board.
Memory is installed using DSIMMs. A maximum of eight DSIMMs may be installed.
Available DSIMMs capacities include 16-Mbyte, 32-Mbyte, and 64-Mbyte.
Additionally, the SPARCstation 20 system supports up to two VSIMMs or one
VSIMM and one NVSIMM. The VSIMM output is provided through the 13W3
connector that is built into the back panel. Optional installation of a second VSIMM
is permitted but requires an AVB with a dedicated 13W3 video output. Although the
second VSIMM (with AVB combination) provides a second video output for the
SPARCstation 20 system, it reduces the number of I/O connectors from four to three.
System Architecture
The SPARCstation 20 system provides the following:
â– SPARC architecture (scalable processor architecture)
â– Memory management unit (MMU)
â– MBus-based system processor architecture
â– SBus-based system bus architecture