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.
hppa/gsckbc(4)
    PC-style keyboard controller.
hppa/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
hppa/asp(4), hppa/cpu(4), hppa/intro(4), hppa/lasi(4), hppa/wax(4)

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