SBus
Year created | 1989 |
---|---|
Created by | Sun Microsystems |
Superseded by | PCI (1997) |
Width in bits | 32 |
No. of devices | 8 masters, unlimited slaves |
Speed | 16.67 MHz - 25 MHz |
Style | Parallel |
SBus is a
The industry's first third-party SBus cards were announced in 1989 by Antares Microsystems; these were a 10BASE2 Ethernet controller, a SCSI-SNS host adapter, a parallel port, and an 8-channel serial controller.
The specification was published by Edward H. Frank and James D. Lyle.[1] A technical guide to the bus was published in 1992 in book form by Lyle,[2] who founded Troubador Technologies. Sun also published a set of books as a "developer's kit" to encourage third-party products.[3]
At the peak of the market over 250 manufacturers were listed in the SBus Product Directory, which was renamed to the SPARC Product Directory in 1996.
SBus is in many ways a "clean" design. It was targeted only to be used with SPARC processors, so most cross-platform issues were not a consideration. SBus is based on a
When the
SBus cards had a very compact form factor for the time. A single-width card was 83.82 millimetres (3.300 in) wide by 146.7 millimetres (5.78 in) long and is designed to be mounted parallel to the motherboard. This allowed for three expansion slots in the slim "pizza box" enclosure of the SPARCstation 1.[4] The design also allows for double- or triple-width cards that take up two or three slots, as well as double-height (two 3x5 inch boards mounted in a "sandwich" configuration) cards.
SBus was originally announced as both a system bus and a peripheral interconnect that allowed input and output devices relatively low latency access to memory.[5] However, soon memory and central processing unit (CPU) speeds outpaced I/O performance. Within a year some Sun systems used MBus, another interconnection standard, as a CPU—memory bus. The SBus served as an input/output bus for the rest of its lifetime.
See also
- List of device bandwidths
References
- ^ a b "PCI:SBus Comparison" (PDF). Sun Microsystems. March 1999. Retrieved May 25, 2011.
- ISBN 978-0-387-97862-8.
- ISBN 978-0-13-107210-7.
- S2CID 20894045.
- S2CID 25815415.