PC Services(London) Ltd. 
Now, What is your Question, Please?
Now, What is your Question, Please?
|
"get me outta this IT hell!" | Hard DrivesStorage Media - Hard Drives There are numerous types of drive used for storing computer data; these include floppy drives, hard drives, CD-ROM drives and so on. These drives use differing types of technologies to store information, including magnetic and optical storage. Modern hard disks consist of one or more magnetic disks contained in a box that is typically 3.5 inches in diameter. Size and speed of the hard drive are decisive factors in a computer's performance. A disk drive is made up of a disk that stores information, a motor that rotates the disk, a magnet, and an actuator with read/write heads attached to suspension arms that magnetically and electronically read and write information on the disk surface. When the motor is powered up the disk rotates and causes the read/write heads to fly above the disk surface on a cushion of air. They are two or three microns above the surface, and the disk can rotate up to 7200 RPM or more, which means that the heads can be travelling at speeds in excess of 64 miles per hour. Under normal operation there is never any head to disk contact. EIDE Hard drives can be distinguished by their interface types. Today's systems generally have either EIDE controllers or SCSI controllers. EIDE (Enhanced Integrated Device Electronics) is the current standard for inexpensive, high performance hard disks. It is the enhanced version of the old IDE standard. EIDE controllers are integrated onto motherboards. The acronym ATA (Advanced Technology Attachment) is synonymous with EIDE. Most modern BIOS software can auto detect an EIDE disk, allowing it to work immediately once it is installed. The hard disk is connected to the motherboard by means of an EIDE signal cable.
Each motherboard has sockets for two EIDE cables (a primary channel and a secondary channel), and has connectors for two units (a master and a slave) on each channel. The EIDE interface is designed for more than just hard disks. It can be used for a variety of devices, including CD-ROM drives, CR-RW drives, DVD drives and other types of storage media. A new PC will usually have two EIDE units connected, a hard disk on the primary master, and a CD-ROM drive on the secondary master. A second hard drive must be placed on the primary EIDE channel's slave connector. Additionally, you also must set jumpers on the disk drive itself to specify if it is to be a master or slave disk. Jumper pins are used to detail the jumper setting that specifies how the drive is to be used.
A typical set-up with four EIDE devices might look like this:
As we've shown, on an EIDE host controller there are sockets for two EIDE cables. For a system with a single hard disk, it should be assigned as primary on the master channel. In general, to achieve optimal performance, if you have two hard disk drives, each should be assigned as masters on the primary and secondary channels. This is because the slave and master sub-channels on a given channel cannot multi-task; only one operation is performed at a time, as opposed to the primary and secondary channels, which are capable of multitasking. SCSI The SCSI (Small Computer System Interface) interface is typically found in high-end systems and servers. The main difference between SCSI and EIDE is that a single SCSI adapter can handle 7 or 15 devices, of varying types (internal or external hard disks, scanners, CD-ROMs, zip drives, etc.). Another difference is that while most modern systems have their EIDE controller as part of the motherboard, SCSI controllers are often a separate expansion card. SCSI drives are faster and generally more robust than EIDE drives. The SCSI system holds its own computer power, thus freeing the CPU. After physically installing the drive you will need to configure it. First, you will need to run FDISK in order to partition it, thereby defining areas of the disk for an operating system to use as a volume. FDISK writes a master partition boot sector on the first sector of the hard disk. This partitioning also prepares the drive for formatting, and tells the ROM BIOS which of the partitions are bootable. If you are unfamiliar with FDISK, we encourage you to read Using the FDISK Utility. Second, you will need to format your disk. There are two format procedures that are required prior to your using a new hard disk:
When you format a floppy diskette, both types of formatting are done simultaneously, but on a hard disk they are separate procedures. The LLF is performed by the manufacturer prior to sale, and for EIDE drives this is usually never done by the end user. The low-level format writes the tracks and sectors on the disk. The HLF is what is done by the DOS FORMAT command. If you are unfamiliar with the DOS FORMAT command, we encourage you to read Using DOS FORMAT. During the high-level format the operating system writes the structures required for managing data on the disk, basically creating a table of contents. |
Send mail to webmaster@pcservices4all.com with questions or comments about this web site. OrSales: sales@pcservices4all.com |
