All about SCSI controller cards

SCSI Controller Cards

Below is a list of SCSI controllers we carry, in two sections: non-RAID and hardware RAID. The non-RAID controllers do not have built-in hardware RAID, but can still be used with host-based RAID setups. Unless otherwise indicated, all PCI-X cards will work in a regular PCI slot as well. Dual channel cards are useful when you have more than a few drives to use with the controller, or you need to mix and match single-ended and LVD devices. 1U form factor cases require low-profile cards. All cards are brand new and come in OEM packaging, unless indicated otherwise (you need to purchase any cables and terminators separately.)

More information about SCSI conectors

More Information

1. Below are the pictures, widths and types of various SCSI connectors. If you find it difficult to identify the connector from the picture, simply measure the width of the connector from edge to edge (excluding any posts) which should match the number in the width column. You can also count the individual "pins" on the connectors which should be 25, 50, 68 or 80 as appropriate. The connectors shown here are the ones that would appear on the devices - cabling would have the opposite gender. The connector type of is an indication of whether the connector applies to an internal or external device, as well as a narrow 8-bit or wide 16-bit device (please see #3 below.)

   	Name	Width	Connector type
   	Centronics/CN 50	2.5"	External Narrow
   	DB25	1.5"	External Narrow
   	HD50/MiniDB50/HPDB50	1.38"	External Narrow
   	IDC50	2.6"	Internal Narrow
   	HD68/MiniD68/HPDB68	1.8"	External Wide
   	HD68/MiniD68/HPDB68	1.8"	Internal Wide
   	0.8mm VHDCI 68/HPCN68	1.25"	External Wide
   	SCA 80/LVD SCA	2.15"	Internal Wide Hotswap

2. Our adapters work with either the older Single-ended (SE) or the newer low-voltage differential (LVD) devices. Please note that while you can attach a slower single-ended device to a SCSI bus shared with faster LVD devices (Ultra2, Ultra160 and Ultra320), all devices on the bus will run at the slower 40MB/sec SE transfer rate. No such concern exists when mixing LVD devices rated at various speeds - each device will run at its (and the controller's) maximum rated speed.
3. All bits on the SCSI bus needs to be terminated, but when you are connecting a wide cable to a narrow device, the device cannot supply the termination for the upper 8 bits of the 16 bit wide signal path. Correct functionality can only be guaranteed by using an adapter with high-byte termination. Most, if not all, suitable adapters we sell have high-byte termination for this purpose.
4. Certain standards exists concerning connector genders: Internal IDC 50 pin SCSI cables have female connectors and the IDC 50 pin drives have male connectors. These are drives rated UltraSCSI or slower. Internal HD 68 pin cables have male connectors and the HD 68 pin drives have female connectors. These are drives rated Ultra2, U160 or U320.
5. External SCSI cables are simpler. The connectors on the cables are typically male and the device connectors will be female.
6. There is no SCA cabling.

What are SCSI adapters?

SCSI Adapters

SCSI adapters are internal or external pieces that convert from one connector type to another, allowing the use of cables and devices with different connectors. The descriptions of our adapters specify the type of connectors on the adapter itself. For example, a 68 pin male to 50 pin female adapter will be used to mate a 68 pin female and a 50 pin male connector. We gave grouped the adapters into three categories depending on whether the devices and cables you are working with are internal or external:

Kind of drivers

External Hitachi 147GB 15K SCSI Hard Drive
Top-notch 15K performance. HD68 U320 interface. Perfect upgrade for any SCSI system. 3yr warranty. PC and MAC compatible.

Part#:
HDS-EXT147G15K

External 500GB SCSI Hard Drive Solution
The ultimate SCSI hard drive! Features an industry proven adapter to convert a 500GB SATA-II drive to SCSI. Very fast performance. 3 year warranty. Assembled and tested prior to shipping. PC & MAC.

Part#:
HDS-EXT500SGT

External 750GB SCSI Hard Drive Solution
The ultimate SCSI hard drive! Features an industry proven adapter to convert a 750GB SATA-II drive to SCSI. Very fast performance. 3 year warranty. Assembled and tested prior to shipping. PC & MAC.

Part#:
H

SCSI connectors

One of the oldest SCSI connectors, the 25-pin DSub connector is the same plug as found on many parallel ports, but SCSI is not interchangeable. It features two rows of low-density pins and thumbscrews.

DB50 - 50 Pin D-Sub

The 50-pin DSub SCSI connector features three rows of low-density pins and thumbscrews. Because of the bulkiness and width of this connector, it is fairly uncommon.

CN50 - 50 pin Centronics

A common SCSI connector on devices is the Centronics 50-pin connector, which features a slot of contacts and wire securing snaps. It is of similar construction to the 36-pin Centronics connector found on parallel printers, but is much wider to accomodate 50 pins. This connector is commonly referred to as SCSI-1.

DH50 - 50 Pin High-Density

Also known as SCSI-2, this connector features two rows of high-density pins with clamping braces. This higher density connector provides the bandwidth of the previous models in much less space.

HS50 - 50 Pin Ribbon

This is the internal companion to the above 50-pin connector sets. The HS50 connector is a crimping connector to mount on ribbon cables, and is almost exclusively used on internal components such as hard drives and optical media drives.

DH68 - 68 Pin High Density

The most common SCSI interface is the 68-pin high-density connector, which features two rows of high-density pins. This connector is known as SCSI-3 and is found on both internal and external components. This connector can also be used for Low-Voltage Differential (LVD) buses.

VHDCI / UHD - 68 pin Ultra-High Density

The Ultra-High Density SCSI connector is an extremely compact 68-pin connector with a slot of contacts and securing screws. This connector is also compatible with LVD buses, and can also be referred to as SCSI-4.

What is SCSI?

SCSI stands for (S)mall (C)omputer (S)ystems (I)nterface. The official name of the SCSI standard is: ANSI X3.131 - 1986.

The SCSI interface is a local bus type interface for connecting multiple devices (up to eight), designated as either initiators (drivers) or targets (receivers).

There are two electrical alternatives for this standard:

1. Single-ended type and
2. Differential type

Single-ended and Differential devices are different and MAY NOT be mixed on the same bus; however, LVD (or 'Low Voltage Differential') SCSI can be used on the same SCSI bus with 'SE' type devices, if:

• Your SCSI card supports this; and
• You are using a multi-mode type terminator, sometimes designated as 'LVD/SE' type.

In a SCSI environment, devices are daisy - chained together using a common cable. Both ends of the cable must be terminated. All signals are common between all SCSI devices.