Parallel SCSI data rate of 640 MB/s. Due to the technical constraints of a parallel bus system, SCSI has since evolved into faster serial interfaces, mainly Serial Attached SCSI and Fibre Channel. The iSCSI protocol doesn't even have a physical definition at all but uses any IP network, usually based on Ethernet. , SCSI interfaces had become impossible to find for laptop computers. Adaptec had years before produced PCMCIA parallel SCSI interfaces, but when PCMCIA was superseded by the ExpressCard Adaptec discontinued their PCMCIA line without supporting ExpressCard. Ratoc produced USB and Firewire to parallel SCSI adaptors, but ceased production when the
Parallel port many Linux distributions and provides an abstract interface to the parallel ports of the system. Access is handled in an open-claim-release-close sequence, which allows for concurrent access in userspace. The older parallel printer ports had an 8-bit data bus and four pins for control output (Strobe, Linefeed, Initialize, and Select In), and five more for control input (ACK, Busy, Select, Error, and Paper Out). Its data transfer speed is at 150 kbit/s. The newer EPPs (Enhanced Parallel Ports) have an 8-bit data bus, and the same control pins as the normal parallel printer port. Newer ports reach speeds of up