16 UCT 502 COMPUTER INSTALLATION SERVICING By Ms

16 UCT 502 COMPUTER INSTALLATION & SERVICING By Ms. D. Megala Assistant Professor Department of Computer Technology DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 1/16/2022 1

HD Controller • Communication between CPU and disk drive • Receives control signals from drive and send to processor • Data is written with write with 3 compensation signal • Early system has IC in motherboard • Later systems has IDE and SCSI controller to manage control to HD 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 2

HD Controller Functional Blocks • • System interface unit Sector buffer RAM HDC BIOS ROM Timing and control unit Hard disk controller Read/write logic Drive interface logic 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 3

HDC Functions • System Interface Unit: • Communication between CPU and HDC is established the system interface unit. • HDC communication to CPU and DMA controller • Sometimes CPU can passed HDC working with DMA controller • CPU sends commands to HDC the hard disk 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 4

HD Controller Functions Sector Buffer RAM: Temporary storage during read and write commands. Data RAM stored information of disk format HDC BIOS ROM: Stores I/O drive for hard disk operation. After restart command or power on ram BIOS will do sell test on HDC 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 5

HD Controller Functions Timing and Control Unit: • Generates different timings and control signals for I/O interface. Read Write Logic: § Converts the system byte from parallel to serial. § Data are analyzed through write precompensation circuit 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 6

HD Controller • Drive Interface Logic: • Function is used to find the error code check • During write operations during read operation 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 7

Interface Types • Connecting HDD to main computer system • H/W interfacing makes physical connection between computer and drive. • S/W interfacing deals computer manages the data instruction. • Multi i/o cards available serial and parallel ports • Two HDD interface types • �IDE • �SCSI • �ST-506/412 and ESDI two popular interface standards. 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 8

IDE • Stands for Integrated Drive Electronics • ST-506/412 interface controller card the expansion slot and drive was connected through cables • Laid restriction shard disk design data transfer techniques • HDD manufacturer controller card integrated reliable and less expensive • All drive electronics installed on drive itself. • Does not need a separate interface card. • “Dumb adapter” used make the connections 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 9

SCSI • • Stands for Small Computer System Interface not drive level interface but system level interface Not controller single device Eight controllers plugged into single SCSI system and communicate each other. • Controllers called host adapter • SCSI card plugged into slot in PC • SCSI not directly works with hard disk. • Disk drive needs controller to talk to SCSI • SCSI interface device connected given unique device identification number called • SCSI ID. • Number helps SCSI controller to identify device during data DRSNSRCAS/CT DEPT/Computer Installation 1/16/2022 & Servicing/Unit II/Hard Disk communication Drive/Ms. D. Megala 10

ATA/EIDE/ATA-2 • IDE and ATA(AT Attachment interface) one and same • ATA formal standard that defines drive and how it operates • IDE trade name and refers to 40 -pin interface • Drive controller architecture designed implement the ATA standard. • ATA was designed for hard disk only • 1990 ATA-2 or Fast standard was introduced 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 11

Feature of ATA-2 • • • Faster PIO(Programmed I/O Faster DMA data transfer modes More powerful drive commands Support for second drive channel Support for block data transfers 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 12

RAID (REDUNDANT ARRAY OF INDEPENDENT DISKS) • Not standard. Means of protecting valuable data by consistent back-up routines. • Controller writes data to one drive, in RAID. • One or more drives made to mirror master drive in real time. • Typical RAID controller supports four general operating modes 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 13

• RAID 0 – Striping • �Striping mode two or more smaller drives from one large drive • �Data are interleaved between multiple drives. • �Performance enhancement rather than fault tolerance • �RAID 0 does not provide redundancy and hence. • RAID 1 - Mirroring • �Writing data onto a pair of drives is called mirroring. • �Data is duplicated data redundancy provided in RAID 1. • �Disk arrays operated in combination of striping and mirroring. 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 14

HD Controller 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 15

HD Controller 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 16

HD Controller 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 17

HD Controller 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 18

HD Controller 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 19

HD Controller 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 20

HD Controller 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 21

HD Controller 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 22

HD Controller 1/16/2022 DRSNSRCAS/CT DEPT/Computer Installation & Servicing/Unit II/Hard Disk Drive/Ms. D. Megala 23