RS-485: Imported from Wikipedia (overwrite)

2026-05-02T18:13:00Z

Imported from Wikipedia (overwrite)

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{{Notability|date=November 2022}}
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{{Infobox computer hardware bus
| name = GSC
| fullname =
| image =
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| caption =
| invent-date =
| invent-name = [[Hewlett-Packard]]
| super-name =
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| replaces =
| width = 32
| numdev =
| speed = 40 MHz
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}}
'''GSC''' is a bus used in many of the [[HP 9000]] workstations and servers. The acronym has various explanations, including ''Gecko System Connect'' (Gecko being the codename of the 712 workstation), ''Gonzo System Connect'' and ''General System Connect''.

GSC was a general [[32-bit]] [[I/O bus]], similar to [[NuBus]] or [[Sun Microsystems|Sun's]] [[SBus]], although it was also used as a [[memory bus|processor bus]] with the [[PA-7100LC]] and [[PA-7300LC]] processors. Several variations were produced over time, the later ones running at 40 MHz:

;GSC-1X: The original GSC bus implemented on PA-7100LC and used in the Gecko (712), Mirage (715) and Electra computers. Peak Bandwidth 142 MB/s w/DMA, 106 MB/s with PIO writes.

;GSC+, a.k.a. "Extended GSC" or "EGSC": Enhancements added for KittyHawk/SkyHawk (U2 chip) that allow for pending transactions. GSC+ enhancements are orthogonal to the GSC-1.5X and GSC-2X enhancements.

;GSC-1.5X: GSC-1X with an additional variable length write transaction.

;GSC-2X: GSC-1.5X with a protocol enhancement to allow data to be sent at double the GCLK rate, with a peak bandwidth of 256 MB/s.

;HSC: High Speed Connect.

Four types of GSC cards were produced: the GIO cards fit into the larger of the two IO card sockets in the 712 workstation. Several were produced, including a second [[RS-232]] serial port, a serial/[[10BASE-T|10BaseT]] combo, a second graphics card and a [[Token Ring]] card.

The 715/Mirage, 725, 735, 755, B-, C-, and J-class workstations, and the D- and R-class servers, used the so-called "EISA [[form factor (design)|form factor]]". Many different types of card were produced, including [[Ethernet#Gigabit Ethernet|Gigabit Ethernet]], single and dual 100 Mbit Ethernet, Ultra-2 [[SCSI]], [[Asynchronous Transfer Mode|ATM]] and graphics.

The K- and T-class servers both used the "3x5" form factor, although the different brackets prevent the cards being interchangeable. [[Fibre channel]] and [[Ethernet#Gigabit Ethernet|Gigabit Ethernet]] cards both exist.

==See also==
*[[List of device bandwidths]]

==References==
*[http://www.parisc-linux.org/glossary/ PA-RISC LINUX - Glossary]

{{Computer-bus}}
{{Hewlett-Packard}}

[[Category:Computer buses]]
[[Category:Hewlett-Packard products]]

GSC bus - Revision history

RS-485: Imported from Wikipedia (overwrite)