GSC, the General (or Gonzo) System Connect is the primary I/O bus of the early HP workstations. On PA7100LC and PA7300LC systems, the processor also sometimes sits on the GSC bus. The bus is 32-bits wide and comes in several flavours. GSC cards are available in many different form factors to fit in various different chassis sizes.
- GSC-1x: The original GSC bus implemented on PCX-L and used in the Gecko, Mirage and Electra computers. Peak Bandwidth 142MB/s w/DMA, 106 MB/s with PIO writes.
- GSC+: 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. Aka "Extended GSC" or "EGSC".
- 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 (Peak bandwidth = 256 MB/s.)
- All versions of the K-Class systems operate the GSC bus at the same speed. The core I/O slots all run at 32MHz. The other slots connected to the Harrier board all run at 40MHz.