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 Adaptec had years before produced PCMCIA parallel SCSI interfaces, but when PCMCIA was superseded by the ExpressCard Adaptec discontinued their PCMCIA line without supporting ExpressCard.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
Serial digital interface application and interoperability. An 8-bit parallel digital interface is defined by ITU-R Rec. 601; this is obsolete (however, many clauses in the various standards accommodate the possibility of an 8-bit interface). In SD and ED applications, the serial data format is defined to 10 bits wide, whereas in HD applications, it is 20 bits wide, divided into two parallel 10-bit datastreams (known as Y and C). The SD datastream is arranged like this: whereas the HD datastreams are arranged like this: For all serial digital interfaces (excluding the obsolete composite encodings), the native color encoding is YCbCr format. The luminance