However, upper back pain is most often due to muscle irritation or joint problems and is usually not a cause for concern. Upper back pain occurring with other symptoms, such as chest pain or difficulty breathing, may be a sign of a heart attack and should be immediately evaluated in an emergency setting.
(Small Computer System Interface) Pronounced scuzzy, SCSI is a hardware interface for up to 15 peripherals connected to one PCI or PCI Express card (SCSI host adapter) on the motherboard. Introduced in 1986 by Shugart Associates (see SASI), this original parallel architecture was largely replaced by a serial version (see serial attached SCSI).
Informally, each standard in the POSIX set is defined by a decimal following the POSIX. Thus, POSIX.1 is the standard for an application program interface in the C language. POSIX.2 is the standard shell and utility interface (that is to say, the user's command interface with the operating system). These are the main two interfaces, but additional interfaces, such as POSIX.4 for thread management, have been developed or are being developed.