DVD-ROM

A new type of read-only compact disc that can hold a minimum of 4.7GB (gigabytes), enough for a full-length movie.

The DVD-ROM specification supports disks with capacities of from 4.7GB to 17GB and access rates of 600 KBps to 1.3 MBps. One of the best features of DVD-ROM drives is that they are backward-compatible with CD-ROMs. This means that DVD-ROM players can play old CD-ROMs, CD-I disks, and video CDs, as well as new DVD-ROMs. Newer DVD players can also read CD-R disks.

DVD-ROMs use MPEG-2 to compress video data.

SPI

(1) Short for Serial Peripheral Interface, a full-duplex synchronous serial interface for connecting low-/medium-bandwidth external devices using four wires. SPI devices communicate using a master/slaverelationship over two data lines and two control lines:

• Master Out Slave In (MOSI): supplies the output data from the master to the inputs of the slaves.
• Master In Slave Out (MISO): supplies the output data from a slave to the input of the master. It is important to note that there can be no more than one slave that is transmitting data during any particular transfer.
• Serial Clock (SCLK): a control line driven by the master, regulating the flow of data bits.
• Slave Select (SS): a control line that allows slaves to be turned on and off with hardware control.

(2) Short for System Packet Interface, a point-to-point interface standard, allows network equipment designers to develop an array of next-generation multi-service switches and routers to support multi-service traffic with aggregate bandwidths up to OC-192 (10 Gb/s) and beyond, enabling them to dramatically increase system performance. It is a family of Interoperability Agreements from the Optical Internetworking Forum (OIF) which include:

• System Packet Interface Level 5 (SPI-5): OC-768 System Interface for Physical and Link Layer Devices. (OIF documentation)
• System Packet Interface Level 4 (SPI-4) Phase 2: OC-192 System Interface for Physical and Link Layer Devices.(OIF documentation)
• System Physical Interface Level 4 (SPI-4) Phase 1: A System Interface for Interconnection Between Physical and Link Layer, or Peer-to-Peer Entities Operating at an OC-192 Rate (10 Gb/s)  (OIF documentation)
• System Packet Interface Level 3: OC-48 System Interface for Physical and Link Layer Devices (OIF documentation)

MIDL

Short for Microsoft Interface Definition Language, MIDL defines interfaces between client and server programs. Microsoft includes the MIDL compiler with the Platform SDK to enable developers to create the interface definition language (IDL) files and application configuration files (ACF) required for remote procedure call interfaces and COM/DCOM interfaces. MIDL also supports the generation of type libraries for OLE Automation. Create client and server programs for heterogeneous network environments that include such operating systems as Unix and Apple. [Source: MSDN Library – MIDL]

FMD-ROM

Introduced by Constellation 3D Inc. (C3D), Fluorescent Multi-Layer Disc (FMD-ROM) holds up to 140 GB of data. This is currently 215 times greater than a CD-ROM (.65 GB) and 23 times greater than a DVD-ROM(6 GB).

FMD-ROM discs contain fluorescent materials embedded in the pits and grooves of all 10+ layers. When in contact with a laser, the fluorescent materials are stimulated to produce coherent and incoherent light; data is stored in the incoherent light.

Because the technology isn’t based on reflection, multiple layers are read at the same time.

With minor re-tooling, FMD-ROM discs are compatible with existing CD-ROM and DVD-ROM drives. Likewise, FMD-ROM drives are backward compatible, accepting CDs and DVDs.

(pronounced as separate letters) Short for Serial Attached SCSI, an evolution of parallel SCSI into a point-to-point serial peripheral interface in which controllers are linked directly to disk drives. SAS is a performance improvement over traditional SCSI because SAS enables multiple devices (up to 128) of different sizes and types to be connected simultaneously with thinner and longer cables; its full-duplex signal transmission supports 3.0Gb/s. In addition, SAS drives can be hot-plugged.

In topologies with more than two connected devices, SAS calls for the use of expander devices to allow for more than one hostto connect to more than one peripheral.

SAS devices can communicate with both SATA and SCSI devices (the backplanes of SAS devices are identical to SATA devices). A key difference between SCSI and SAS devices is the addition in SAS devices of two data ports, each of which resides in a different SAS domain. This enables complete failover redundancy as if one path fails, there is still communication along a separate and independent path.