Chapter 4 PA-RISC Computer Systems - OpenPA.net

HP 9000/C100 & C110 Internals
Buses
� Runway CPU/memory bus (100 MHz 800 MB/s peak data rate on C100, 120 MHz, 960 MB/s on
C110)
� GSC general system-level I/O bus
� EISA additional expansion I/O bus
� SCSI-2 single-ended bus
� SCSI-2 Fast-Wide high-voltage differential main storage I/O bus
Memory
� 72-pin ECC SIMMs, 60ns or faster
� Bus width: 128 data bits with 16 check bits
� Up to 8-way interleaving
� 400 MB/s (C100), 480 MB/s (C110) peak bandwidth
� Takes 16-128 MB modules
� Eight slots
� 32 MB (2×16) minimum, 1 GB (8×128) maximum
Expansion
� One slot for a GSC (EISA formfactor) card
� Three slots for either GSC (EISA formfactor) or EISA cards
� I/O slot layout (from top to bottom):
Drives
1. EISA or GSC
2. EISA or GSC
3. EISA or GSC (for secondary graphics)
4. GSC (for primary graphics)
The disk-slider can accomodate up to three SCSI drives and one floppy drive simultaneously, the internal
cabling (usually) includes one Wide-SCSI cable with three 68-pin connectors and a HVD-terminator at
the end, one Narrow-SCSI with one 50-pin connector and one cable for the floppy.
The Narrow-SCSI cable is normally used for the external-accessible half-height 5.25″ CD/DAT drive,
although it is of course also possible to connect a 50-pin SE hard drive. The cable can also be easily
replaced with a variant with more connectors to use up to three 50-pin SE hard drives. The PDC can
boot off these SE drives.
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