Hard Drive 7 1 Section Objectives After completing this section you will be able to Install or replace a floppy drive Define and explain fundamental hard drive terminology Compare and contrast IDE and SCSI technologies 7 2 Floppy Drive Overview The floppy drive subsystem consists of three main parts 1 the electronic circuits or the controller 2 the 34 pin ribbon cable and 3 the floppy drive The electronic circuits give the floppy drive instructions The electronic circuits can be built into the motherboard or on an adapter The floppy cable connects the floppy drive to the electronic circuits The floppy drive allows saving data to disk media 7 3 Floppy Media Disk also called floppy disk The media inserted in a floppy drive Write Protect Window A small window in the corner of a floppy with a sliding tab to open or close the window If the window is open the disk is write protected 1 44 MB Disks 3 5 today s floppy disks 7 4 Floppy Media 1 44MB with write Protect and high density windows Floppy Figure 7 1 7 5 Floppy Drive Construction Floppy drives have two read write heads that place the data onto the disk Floppy disks are inserted between the two read write heads in the floppy drive The disk turns inside the disk jackets and the floppy drive heads physically touch and scan the disks to read and write data Over time the read write heads become dirty When a technician sees read write errors occurring the first step is to clean the read write heads 7 6 Floppy Disk Geometry When a disk is formatted concentric circles called tracks are drawn on that disk 1 44MB disks have 80 tracks Sector Tracks are further subdivided into pie shaped wedges A sector is the section defined between a tract and an intersecting line and holds 512 bytes of information Cluster The minimum amount of space one file occupies On a floppy disk a cluster is 1024 bytes or two sectors 7 7 Floppy Disk Geometry Disk with 80 tracks Floppy Figure 7 2 7 8 Floppy Disk Geometry Sectors and sector numbering Floppy Figure 7 3 7 9 Floppy Drive Installation Installation of floppy drives is simple after doing some preliminary homework An available drive bay An available power connection A motherboard floppy connector available or install an additional adapter A floppy cable 7 10 Floppy Drive Installation Floppy Connector on Motherboard Floppy Figure 7 4 7 11 Floppy Drive Configuration Floppy drive cable Floppy Figure 7 5 7 12 Floppy Drive Installation Pin 1 on the cable attaches to Pin 1 on the connector Pin 1 is identified by a red stripe on the cable Most manufacturers identify Pin 1 in writing on the motherboard Installing the floppy is mounting the drive to the case and connecting the cable from the drive to the motherboard or adapter 7 13 Hard Drive Overview Hard drives are a popular devices for storing data The hard drive subsystem can have up to three parts The hard drive Cables that attach to an adapter or the motherboard Control circuits located on an adapter or the motherboard 7 14 Hard Drive Geometry Components of a Hard Drive Platters are multiple hard metal surfaces contained in the hard drive Read Write Heads write and read the 1s and 0s to and from the hard drive surface Head Crash When a read write head touches the hard drive platter Track Concentric circle on a hard drive platter Cylinder One corresponding track on all surfaces of a hard drive Sectors Each track is divided into sectors of 512 bytes 7 15 Hard Drive Geometry Hard Drive Geometry IDE SCSI Figure 7 6 7 16 Hard Drive Geometry Cylinder versus tracks IDE SCSI Figure 7 8 7 17 Hard Drive Interfaces Overview There are two major hard drive interfaces IDE integrated drive electronics Also known as ATA AT Attachment standard IDE is most common in home office computers SCSI small computer system interface SCSI is most common in network servers 7 18 IDE Integrated Drive Electronics IDE Integrated Drive Electronics is used with hard drives as well as tape Zip CD and DVD drives Two types of IDE PATA Parallel ATA Older ATA type PATA uses a 40 pin cable to connect the IDE hard drive to the motherboard or an adapter and transfers 16 bits of data at a time SATA Serial ATA Is a point to point interface in which each device connects to the host through a dedicated link and has the entire interface bandwidth ATA 1 Original IDE interface standard ATA 2 Faster transfer rates than ATA 1 DMA mode direct access mode DMA is supported by ATA 2 It allows data transfer between RAM and the hard drive without going through the CPU UDMA ultra DMA Also known as bus master DMA Latest type of DMA 7 19 IDE Integrated Drive Electronics IDE PATA Standards IDE SCSI Table 7 2 7 20 SCSI Small Computer System Interface SCSI Small Computer System Interface is an interface standard that connects multiple small devices to the same adapter via a SCSI bus SCSI bus is the bus shared by all devices that attach to one SCSI adapter Host Adapter connects the SCSI device to the motherboard and coordinates the activities of other devices connected 7 21 SCSI Small Computer System Interface SCSI standards IDE SCSI Table 7 3 7 22 Drive Configuration Overview The configuration of a hard drive usually includes setting jumpers on the drive terminating properly and performing a few software commands 7 23 PATA IDE Device Configuration The steps for installing a PATA device Do not remove the device from the anti static bag until you are ready to install Follow proper anti static procedure Touch the device by the sides and do not handle the electronics or connectors Turn off the power and remove the power cord Configure jumpers according to the number of devices to be attached to the cable Mount and secure the device Attach the cables Configure BIOS if needed If the device is a hard drive prepare it as specified in the chapter 7 24 PATA IDE Device Configuration PATA IDE Hard Drives are normally configured using jumpers Single IDE setting is used when only one devices connects to the IDE cable Master IDE setting is a jumper setting used to configure an IDE device and is the controlling device on the interface Slave IDE setting is an IDE setting for the second device added to the IDE cable The device should be a slower device than the master Cable Select is a setting used on IDE devices when a special cable determines which device is the master and which one is the slave DASP Drive Active Slave Present is a signal in the ATA interface of the IDE connector that is used to indicate the presence of a slave IDE device