1 / 40

Chapter 8

Chapter 8. All About SCSI. You Will Learn…. 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. SCSI Basics.

hewitt
Download Presentation

Chapter 8

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 8 All About SCSI

  2. You Will Learn… • 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. SCSI Basics • 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. The SCSI Subsystem • 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. The SCSI Subsystem • Every SCSI bus subsystem requires a SCSI controller and unique SCSI IDs assigned to each device, including the host adapter

  6. The SCSI Subsystem

  7. IDE vs. SCSI Bus Communication

  8. Issues to Consider when Selecting a Host Adapter • BIOS • Expansion slot • Bus mastering

  9. Vendors for SCSI Host Adapters

  10. SCSI Device Drivers • 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. Variations in SCSI • Bus width • Signaling methods used on SCSI cables • Connectors used with SCSI cables • Termination • SCSI-1, SCSI-2, and SCSI-3

  12. Bus Width • Narrow SCSI (8 bits) • Wide SCSI (16 bits)

  13. Signaling Methods Usedon SCSI Cables • 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. Signaling Methods on SCSI Cables

  15. SCSI Cables

  16. Signaling Methods on SCSI Cables

  17. Connectors for SCSI Cables

  18. Connectors for SCSI Cables

  19. Termination • 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. Termination

  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 SCSI-1, SCSI-2, and SCSI-3

  22. Comparing IDE and SCSI • 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 continued…

  23. Comparing IDE and SCSI • 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 continued…

  24. Comparing IDE and SCSI • 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

  25. SCSI Installation • 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

  26. Installing a Host Adapter Card with Windows 9x/2000/XP • 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

  27. Installing a Host Adapter Card with Windows 9x/2000/XP

  28. Installing a Host Adapter Card with Windows 9x/2000/XP

  29. Setting Device IDs During Installation • 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

  30. Setting Device IDs During Installation • 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

  31. Setting External Device IDs

  32. Setting Internal Device IDs

  33. Installing a SCSI Hard Drive • 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

  34. Troubleshooting SCSI Devices • General tips • Installation problems • Booting problems

  35. General Troubleshooting Tips • Keep notes and read documentation • Add one SCSI device at a time • Use good quality components • Limit cable length

  36. Problems Installing SCSI Devices • 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

  37. Booting Problems • 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

  38. Chapter Summary • How SCSI technology works to provide better performance and greater expansion capabilities for many internal and external devices • Advantages and disadvantages of SCSI

More Related