Pizza box form factor
In computing, a pizza box is a style of case for computers or network switches. Cases of this type tend to be wide and flat, normally one or two rack units (1U or 2U, 1¾ or 3½ inch, 4.4 or 8.9 cm) in height, thus resembling pizza delivery boxes.
The first computers generally referred to as pizza box systems were high-end desktop systems, such as Sun Microsystems workstations sold in the late 1980s, most notably the SPARCstation 1 and SPARCstation 5. Other notable examples are the SGI Indy, the NeXTstation, Macintosh LC, and Amiga 1000: most were considered to be among the highest performing computers of their generations.
The original SPARCstation 1 design included an expansion bus technology, SBus, expressly designed for the form factor; expansion cards were small, especially in comparison to other expansion cards in use at the time such as VMEbus, and were mounted horizontally instead of vertically. PC compatible computers in this type of case typically use the PCI expansion bus and are usually either limited to 1 or 2 horizontally placed expansion cards or require special low profile expansion cards, shorter than the PCI cards used in regular PCs.[1]
The density of computing power and stackability of pizza box systems also made them attractive for use in data centers. Systems originally designed for desktop use were placed on shelves inside of 19-inch racks, sometimes requiring that part of their cases be cut off in order for them to fit.
Since the late 1990s, pizza boxes are a common form factor in data centers or industrial applications where rack space and density are critical. Servers in this form factor, as well as higher end Ethernet switches, are now designed for rack mounting. Rack mount 1U computers come in all types of configurations and depths.
[edit] References
- ^ "Low-Profile PCI". PCI-SIG Frequently Asked Questions. PCI-SIG. http://www.pcisig.com/news_room/faqs#low_profile_pci. Retrieved 2008-02-17.
[edit] External links
- Pizza box in the Jargon File
