1. Princess Sumaya Univ. Computer Engineering Dept. Chapter 6:

2. Princess Sumaya University 22540 – Computer Arch. & Org (2) Computer Engineering Dept. 1 / 12 I/O Connection Main Memory Interrupts Memory I/O Interconnect CacheCache ProcessorProcessor I/O Controller Disk NetworkNetwork I/O Devices

3. Princess Sumaya University 22540 – Computer Arch. & Org (2) Computer Engineering Dept. 2 / 12 Magnetic Disk Nonvolatile Tracks & Sectors Recorded Information Sector Number, Gap, Data, ECC, Gap, Next Sector Num. Rotational Latency 5400 RPM (½ rotation / 5400) = 5.6 ms Transfer Time Sector: 100 MB/s Cache: 375 MB/s = 3 Gbps SATA-2

4. Princess Sumaya University 22540 – Computer Arch. & Org (2) Computer Engineering Dept. 3 / 12 Disk Interface Advanced Technology Attachment SATA (Serial) Small Computer Systems Interface SCSI (Parallel) SAS (Serial Attached SCSI)

5. Princess Sumaya University 22540 – Computer Arch. & Org (2) Computer Engineering Dept. 4 / 12 Flash Storage Semiconductor Non Volatile (EEPROM) Faster, Smaller and Lower Power Higher Cost Block R/W Wearout (10,000 ~ 100,000 Writes per Cell) Wear Leveling (Remap Blocks) Solid State Disk (SSD) Hybrid Hard Disk

6. Princess Sumaya University 22540 – Computer Arch. & Org (2) Computer Engineering Dept. 5 / 12 Busses Processor-Memory Bus Short, High Speed and Matched Width I/O Bus Can be Lengthy and Connect Many Types Often Have a Wide Range Bandwidth

7. Princess Sumaya University 22540 – Computer Arch. & Org (2) Computer Engineering Dept. 6 / 12 I/O Transaction Two Parts Sending Memory Address Sending or Receiving Data Synchronous All Devices on the Bus Run on the Same Clock Rate Clock Skew Limits Length Asynchronous External: Firewire, USB, etc. Internal: PCI Express, SATA, etc. Handshaking

8. Princess Sumaya University 22540 – Computer Arch. & Org (2) Computer Engineering Dept. 7 / 12 Parallelism & I/O Redundant Array of Inexpensive Disks (RAID) RAID 0 Striping BLK 0 BLK 2 BLK 4 BLK 6 BLK 1 BLK 3 BLK 5 BLK 7

9. Princess Sumaya University 22540 – Computer Arch. & Org (2) Computer Engineering Dept. 8 / 12 Parallelism & I/O Redundant Array of Inexpensive Disks (RAID) RAID 0 Striping RAID 1 Mirroring BLK 0 BLK 1 BLK 2 BLK 3 BLK 0 BLK 1 BLK 2 BLK 3

10. Princess Sumaya University 22540 – Computer Arch. & Org (2) Computer Engineering Dept. 9 / 12 Parallelism & I/O Redundant Array of Inexpensive Disks (RAID) RAID 0 Striping RAID 1 Mirroring RAID 2 Error Detection & Correction Code Bit 0 Bit 2 Bit 4 Bit 6 Bit 1 Bit 3 Bit 5 Bit 7 Parity

11. Princess Sumaya University 22540 – Computer Arch. & Org (2) Computer Engineering Dept. 10 / 12 Parallelism & I/O Redundant Array of Inexpensive Disks (RAID) RAID 0 Striping RAID 1 Mirroring RAID 2 Error Detection & Correction Code RAID 3 Bit-Interleaved Parity Byte 0 Byte 2 Byte 4 Byte 6 Byte 1 Byte 3 Byte 5 Byte 7 Parity

12. Princess Sumaya University 22540 – Computer Arch. & Org (2) Computer Engineering Dept. 11 / 12 Parallelism & I/O Redundant Array of Inexpensive Disks (RAID) RAID 0 Striping RAID 1 Mirroring RAID 2 Error Detection & Correction Code RAID 3 Bit-Interleaved Parity RAID 4 Block-Interleaved Parity BLK 0 BLK 2 BLK 4 BLK 6 BLK 1 BLK 3 BLK 5 BLK 7 Parity

13. Princess Sumaya University 22540 – Computer Arch. & Org (2) Computer Engineering Dept. 12 / 12 Parallelism & I/O Redundant Array of Inexpensive Disks (RAID) RAID 0 Striping RAID 1 Mirroring RAID 2 Error Detection & Correction Code RAID 3 Bit-Interleaved Parity RAID 4 Block-Interleaved Parity RAID 5 Distributed Block- Interleaved Parity BLK 0 BLK 2 Parity BLK 6 BLK 1 Parity BLK 4 BLK 7 Parity BLK 3 BLK 5 Parity

14. Princess Sumaya University 22540 – Computer Arch. & Org (2) Computer Engineering Dept. Chapter 6