GSC(4)

NAME
gsc - General System Connect bus on HP 9000/700 machines

SYNOPSIS
gsc* at lasi?
gsc* at asp?
gsc* at wax?

DESCRIPTION
This is the core I/O bus for all HP 9000/700 workstations. All I/O subsystems connect to this bus. The devices can be either on separate chips, expansion cards or on an integrated megacell, like the LASI MBA.

The GSC bus is a 32-bit wide, address and data multiplexed bus. In its "standard" implementation it has a maximum throughput of 160MB/s, the "2x" implementation reaches up to 250MB/s. Some HPPA CPUs directly attach to this bus, namely the PA7100LC and PA7300LC.

As for the expansion cards, there are different form-factors, depending on bus-speed (standard or 2x) and specific models. The standard formfactor is the "EISA form-factor"; cards that look like typical EISA cards with a different connector (100-pin female EBBL). The Series 712 have their own special type of GSC expansion cards, called the "GIO form-factor", which is quite small and mostly has only one VLSI chip on it (in most cases LASI/WAX). Newer systems sometimes feature the "HSC formfactor", which is a 1U-VME card-like expansion card with a 100-pin male pin+socket connector. Mixing cards with different speeds is supported but downgrades the performance of the whole I/O-subsystem.

SUPPORTED DEVICES
The system includes machine-dependent GSC drivers, sorted by driver name:

com(4)
    RS-232 ports.
gsckbc(4)
    PC-style keyboard controller.
harmony(4)
    CS4215/AD1849 audio.
hil(4)
    Human Interface Loop, for HP-proprietary input devices like keyboard and mice.
iee(4)
    Intel i82596 DX/CA 32-bit LAN coprocessor.
lpt(4)
    Centronics printer port.
oosiop(4)
    Symbios/NCR 53C700 SCSI I/O Processor.
osiop(4)
    Symbios/NCR 53C710 SCSI I/O Processor.

Some of these GSC devices also have PCI, EISA, or ISA equivalents. These are listed in pci(4), eisa(4), or isa(4).

SEE ALSO
asp(4), cpu(4), intro(4), lasi(4), wax(4)

HISTORY
The gsc driver appeared in OpenBSD 2.6. It was ported to NetBSD 1.6 by Matthew Fredette.