======================PROTOCOLS_SCSI============================================ Apple SCSI HDI-30 30 PIN UNKNOWN CONNECTOR Pin Name Dir Description 1 n/c Reserved for SCSI disk mode. 2 /DB0 [<->] Bit 0 of SCSI data bus 3 GND [---] Ground 4 /DB1 [<->] Bit 1 of SCSI data bus 5 TPWR [<->] Termination power 6 /DB2 [<->] Bit 2 of SCSI data bus 7 /DB3 [<->] Bit 3 of SCSI data bus 8 GND [---] Ground 9 /ACKS [<--] Handshake signal. When low acknowledges a request for data transfer 10 GND [---] Ground 11 /DB4 [<->] Bit 4 of SCSI data bus 12 GND [---] Ground 13 GND [---] Ground 14 /DB5 [<->] Bit 5 of SCSI data bus 15 GND [---] Ground 16 /DB6 [<->] Bit 6 of SCSI data bus 17 GND [---] Ground 18 /DB7 [<->] Bit 7 of SCSI data bus 19 /DBP [<->] SCSI data bus parity bit 20 GND [---] Ground 21 /REQ [-->] Request for a data transfer 22 GND [---] Ground 23 /BSY [<->] When active (low) indicates that SCSI data bus is busy 24 GND [---] Ground 25 /ATN [<--] When active (low) indicates an attention condition 26 /C/D [-->] When active (low) indicates that data is on SCSI bus. When high, indicates that control signals are on the bus 27 /RST [<->] SCSI bus reset 28 /MSG [-->] Indicates the message phase 29 /SEL [<->] SCSI select 30 /I/O [-->] Controls direction of data output. When high, data is input author: Tomi Engdahl SCSI Background It all started back in 1979 when the diskdrive manufacturer come with the bright idea to make a new transfer protocol. The protocol was named Shugart Associates Systems Interface, SASI. This protocol wasn't an ANSI standard, so NCR join Shugart and the ANSI committee X3T9.2 was formed. The new name for the protocol was, Small Computer Systems Interface, SCSI. Common Command Set, CCS, was added in 1985. ANSI finished the SCSI standard in 1986. SCSI-II devices was released in 1988 and was an official standard in 1994. SCSI-III is currently not yet official. Usage SCSI is used to connect peripherals to an computer. It allows you to connect harddisks, tape devices, CD-ROMs, CD-R units, DVD, scanners, printers and many other devices. SCSI is in opposite to IDE/ATA very flexible. Today SCSI is most often used servers and other computers which require very good performance. IDE/ATA is more popular due to the fact that IDE/ATA devices tend to be cheaper. Definitions SCSI Short for Small Computer Systems Interface. The original CSI protocol. ANSI standard X3.131-1996. Busspeed 5 MHz. Datawidth 8 bits. SCSI-II adds support for CD-ROM's, scanners /tapedrives. ----------------------PROTOCOLS_SCSI---------------------- Apple SCSI HDI-30 30 PIN UNKNOWN CONNECTOR Pin Name Dir Description 1 n/c Reserved for SCSI disk mode. 2 /DB0 [<->] Bit 0 of SCSI data bus 3 GND [---] Ground 4 /DB1 [<->] Bit 1 of SCSI data bus 5 TPWR [<->] Termination power 6 /DB2 [<->] Bit 2 of SCSI data bus 7 /DB3 [<->] Bit 3 of SCSI data bus 8 GND [---] Ground 9 /ACKS [<--] Handshake signal. When low acknowledges a request for data transfer 10 GND [---] Ground 11 /DB4 [<->] Bit 4 of SCSI data bus 12 GND [---] Ground 13 GND [---] Ground 14 /DB5 [<->] Bit 5 of SCSI data bus 15 GND [---] Ground 16 /DB6 [<->] Bit 6 of SCSI data bus 17 GND [---] Ground 18 /DB7 [<->] Bit 7 of SCSI data bus 19 /DBP [<->] SCSI data bus parity bit 20 GND [---] Ground 21 /REQ [-->] Request for a data transfer 22 GND [---] Ground 23 /BSY [<->] When active (low) indicates that SCSI data bus is busy 24 GND [---] Ground 25 /ATN [<--] When active (low) indicates an attention condition 26 /C/D [-->] When active (low) indicates that data is on SCSI bus. When high, indicates that control signals are on the bus 27 /RST [<->] SCSI bus reset 28 /MSG [-->] Indicates the message phase 29 /SEL [<->] SCSI select 30 /I/O [-->] Controls direction of data output. When high, data is input author: Tomi Engdahl SCSI Background It all started back in 1979 when the diskdrive manufacturer come with the bright idea to make a new transfer protocol. The protocol was named Shugart Associates Systems Interface, SASI. This protocol wasn't an ANSI standard, so NCR join Shugart and the ANSI committee X3T9.2 was formed. The new name for the protocol was, Small Computer Systems Interface, SCSI. Common Command Set, CCS, was added in 1985. ANSI finished the SCSI standard in 1986. SCSI-II devices was released in 1988 and was an official standard in 1994. SCSI-III is currently not yet official. Usage SCSI is used to connect peripherals to an computer. It allows you to connect harddisks, tape devices, CD-ROMs, CD-R units, DVD, scanners, printers and many other devices. SCSI is in opposite to IDE/ATA very flexible. Today SCSI is most often used servers and other computers which require very good performance. IDE/ATA is more popular due to the fact that IDE/ATA devices tend to be cheaper. Definitions SCSI Short for Small Computer Systems Interface. The original CSI protocol. ANSI standard X3.131-1996. Busspeed 5 MHz. Datawidth 8 bits. SCSI-II adds support for CD-ROM's, scanners /tapedrives. SCSI Pronounced "scuzzy," small computer system interface is a method of adding additional devices, such as hard drives or scanners, to the computer. AGP Accelerated Graphics Port high-speed connection used by graphics card to interface with the computer. Sound card - used by the computer to record and play audio by converting analog sound into digital information Graphics card translates image data from the computer into a format that can be displayed by the monitor. No matter how powerful components inside your computer are, you need a way to interact with them. This interaction is called input/output (I/O). The most common types of I/O in PCs are: Monitor monitor is primary device for displaying information Keyboard - keyboard is the primary device for entering information into the computer. Mouse mouse is the primary device for navigating and interacting with computer Removable storage Removable-storage devices allow you to add new information to your computer very easily, as well as save information that you want to carry to different location. Floppy disk most common form of removable storage, floppy disks are extremely inexpensive and easy to save information to. CD-ROM CD-ROM (compact disc, read-only memory) a popular form of distribution of commercial software. Many systems now offer CD-R (recordable) and CD-RW (rewritable), can also record. Flash memory Based on a type of ROM called electrically erasable programmable read-only memory (EEPROM), Flash memory provides fast, permanent storage. CompactFlash, SmartMedia and PCMCIA cards are all types of Flash memory. DVD-ROM DVD-ROM (digital versatile disc, read-only memory) is similar to CD-ROM but is capable of holding much more information. Ports Parallel port is commonly used to connect a printer. Serial port is typically used to connect an external modem. Universal Serial Bus (USB) - Quickly becoming the most popular external connection, USB ports offer power and versatility and are incredibly easy to use. Firewire (IEEE 1394) Firewire is a very popular method of connecting digital-video devices, such as camcorders or digital cameras, to your computer. Internet/network connection Modem This is standard method of connecting to the Internet. Local area network (LAN) card - This is used by many computers, particularly those in an Ethernet office network, to connected to each other. Cable modem Some people now use the cable-television system in their home to connect to the Internet. Digital Subscriber Line (DSL) modem - This is a high-speed connection that works over a standard telephone line. Very high bit-rate DSL (VDSL) modem - A newer variation of DSL, VDSL requires that your phone line have fiber-optic cables.