1
|
|
2
|
- About basics of SCSI (Small Computer System Interface) technology and
components
- How SCSI hard drives compare to IDE drives
- How to install a SCSI device
- Some troubleshooting tips for SCSI
|
3
|
- Standard for communication between subsystem of peripheral devices and
system bus
- Bus can contain/be used by up to 7 or 15 devices, depending on SCSI
standard
- Bus controller can be either:
- An expansion card (host adapter)
- Embedded on motherboard
- Faster, more expensive, more difficult to install than similar IDE
devices
|
4
|
- Host adapter
- Card inserted onto expansion slot on mother board
- Manages all devices on SCSI bus
- Supports internal and external SCSI devices
- Forms a single daisy chain with devices
- Device drivers
- Enable OS to communicate with a host adapter
|
5
|
- Every SCSI bus subsystem requires a SCSI controller and unique SCSI IDs
assigned to each device, including the host adapter
|
6
|
|
7
|
|
8
|
- BIOS
- Expansion slot
- Bus mastering
|
9
|
|
10
|
- Enable OS to communicate with a host adapter
- Two popular driver types
- ASPI (Advanced SCSI Programming Interface) – more popular of the two
- CAM (Common Access Method)
|
11
|
- Bus width
- Signaling methods used on SCSI cables
- Connectors used with SCSI cables
- Termination
- SCSI-1, SCSI-2, and SCSI-3
|
12
|
- Narrow SCSI (8 bits)
- Wide SCSI (16 bits)
|
13
|
- Single-ended (SE)
- Send a signal on pair of twisted wires; one carries voltage, the other
is a ground
- Differential
- Send a signal on pair of twisted wires; both carry voltage, and the
signal is calculated to be the difference between the two voltages
- High Voltage Differential (HVD)
- Low Voltage Differential (LVD)
|
14
|
|
15
|
|
16
|
|
17
|
|
18
|
|
19
|
- Prevents echo effect from electrical noise and reflected data at end of
SCSI daisy chain
- Single-ended SCSI cables use:
- Passive terminators
- Active terminators
- Forced perfect terminators (FPTs)
- Differential cables use either HVD or LVD terminators
|
20
|
|
21
|
- SCSI-1 = Regular SCSI
- 8-bit data bus
- 7 possible devices
- SCSI-2 = Fast SCSI
- Common command set
- 16-bit data bus
- 15 possible devices
- Mandatory parity checking
- SCSI-3 = Ultra SCSI
- Supports both parallel and serial data transmission
- Supports FireWire connections
- Data transfer of 320 MB/sec
|
22
|
|
23
|
|
24
|
- IDE supports only four internal devices; SCSI supports both internal and
external and allows you to add more
- SCSI devices are generally of higher quality than IDE devices and more
expensive
- IDE devices require separate IRQ for each device; SCSI requires only one
for entire chain
|
25
|
- Both are generally backward-compatible
- SCSI hard drive with supporting host adapter and cable costs more than
an IDE hard drive
- SCSI subsystem provides faster data transfer than an IDE drive
- SCSI generally provides better performance than IDE; often used on
high-demand servers
|
26
|
- Good host SCSI host adapter allows connection of other SCSI devices to
it
- With SCSI, two or more devices can operate simultaneously; with IDE,
only one IDE drive on an IDE channel can be busy at a time
|
27
|
- Set jumpers or switches on host adapter and install it on motherboard
- Assign SCSI ID with jumpers or switches
- Attach cabling to host adapter and each device
- Verify termination at both ends of daisy chain
- Power up one device at a time
- Install drivers and software
|
28
|
- Install card in expansion slot
- Change/verify default settings using setup program
- Verify settings under Advanced Configuration Options
- Windows supports host adapter; it loads device drivers automatically and
installs host adapter
- Use Device Manager to verify correct installation of host adapter
- Install external SCSI device
|
29
|
|
30
|
|
31
|
- With SCAM-compliance, SCSI IDs are assigned automatically
- Without SCAM compliance, set device SCSI IDs manually
- Each ID must be unique; no two devices on same SCSI channel can have
same ID number
- For narrow SCSI, use IDs 0-7
- For wide SCSI, use IDs 0-15
- Host adapter usually has ID 7
|
32
|
- To set IDs for external devices, use either push-button selector or
rotary selector
- To set IDs for internal device, use set of jumpers on the device
|
33
|
|
34
|
|
35
|
- Make sure host adapter and cables are compatible with SCSI drive
- Configure SCSI host adapter and SCSI hard drive so they can communicate
with each other as follows:
- Set SCSI IDs
- Disable/enable disk drive and hard drive controllers
- Check terminating resistors
- Run CMOS setup for a SCSI system
- Load SCSI device drivers
|
36
|
- General tips
- Installation problems
- Booting problems
|
37
|
- Keep notes and read documentation
- Add one SCSI device at a time
- Use good quality components
- Limit cable length
|
38
|
- Turn on external devices first, then computer
- Check connections
- Verify correct termination (common cause of problems)
- Verify most updated BIOS
- Install PCI host adapter in PCI bus that supports bus mastering
|
39
|
- Confirm BIOS setup drive configuration is set to “No Drives Installed”
- Verify that SCSI drive is partitioned, has a primary partition, and boot
partition is set as active
- Back up SCSI hard drive and do low-level format on it
|
40
|
- How SCSI technology works to provide better performance and greater
expansion capabilities for many internal and external devices
- Advantages and disadvantages of SCSI
|