hard disk drive or hard drive is the main location where all data
is stored. Most hard disk drives consist of spinning platters of aluminum,
glass or ceramic that are coated with a magnetic media.
A single hard disk usually consists of several platters. Each platter
requires two read/write heads, one for each side. All the read/write
heads are attached to a single access arm so that they cannot move
independently. Each platter has the same number of tracks, and a track
location that cuts across all platters is called a cylinder. For example,
a typical 84mb hard disk for a PC might have two platters (four sides)
and 1,053 cylinders.
drive manufacturers: fujitsu, ibm/hitachi, maxtor, seagate, western
for buying a hard drive
You should make sure there's space in the case for another drive.
Most desktop PC cases have at least one, and sometimes several spaces,
internal drive bays--places where you can mount extra hard drives.
But check your manual and open up the case. Some of the smaller low-profile
computer cases don't have room for additional internal hard drives,
so you won't be able to use both the your old and a new drive in the
same computer case. In which case you will need to buy an external
Capacity typical hard drives are about 100GB they
can go up to 1 TB the more information such as pictures, files, music
and videos your going to store the more space your going to need.
RPM rotation per minute The best is 15,000 rpm however you
should consider buying a hard drive with a fast rotational speed of
7,200 revolutions per minute (rpm) or higher. You should expect to
spend less for a slower 5,400-rpm hard drive.
Seek Time you should look for an average seek time of fewer
than 4.7 milliseconds (ms), and a data transfer rate of at least 15
megabytes (MB) per second. The actual sustained speed of the drive
will be less than the maximum "burst" speed.
Buffer 8MB or better: When a system requests data, a hard
drive will not only fetch what is requested, but it will also load
its buffer memory with extra information that the processor is likely
to ask for next. While a 2MB buffer is good, that's plenty of room
to keep the data flowing, I found that drives with 8MB performed is
best! for disk-intensive tasks.
Internal Hard Drives
Parallel ATA 33, 66, 100, 133MB/s
Serial ATA 150-300MB/s
External Hard Drives
USB 12Mbps up to 480Mbps
Firewire 400Mbps up to 800Mbps
External Hard Drives. External drives is a good idea
if you need to lock up important data or you need to transport a lot
of data to another PC. Note external hard drives cost quite a bit
more than internal drives and usually require an FireWire or USB 2.0
There are three main types of internal hard drive Parallel
ATA, Serial ATA and SCSI.
Below is a picture of what the inside of the hard disk drive looks
like. The Hard disk drive has four main components. The head actuator
controls the head arm, which reads the information off of the disk
platter. The chassis encases and holds all the hard disk drive components.
Platter - The actual fixed disk within the hard disk
drive. There can be several platters within the hard drive
Heads - Each side of a platter
Tracks - Large sections that completely circle the
Sector - Section on the track
Cluster - Smallest unit of measurement that a hard
drive will read
Cylinder - Tracks of the same diameter on each platter
of Hard Drives
Abbreviation of either Intelligent Drive Electronics or Integrated
Drive Electronics, depending on who you ask. An IDE interface is an
interface for mass storage devices in which the controller is integrated
into the disk or CD-ROM drive. IDE usually contains one controller
and 40 pins where you can install up to only 2 devices a typical speed
of an IDE drives is about 3/MBs
EIDE Short for Enhanced IDE, a newer version of the IDE mass
storage device interface standard developed by Western Digital Corporation.
It supports data rates of between 4 and 16.6 MBps, about three to
four times faster than the old IDE standard. In addition, it can support
mass storage devices of up to 8.4 gigabytes, whereas the old standard
was limited to 528 MB. Because of its lower cost, enhanced EIDE has
replaced SCSI in many areas.
ATA: Known also as IDE, supports one or two hard drives,
a 16-bit interface and PIO modes 0, 1 and 2.
ATA-2: Supports faster PIO modes (3 and 4) and multiword DMA
modes (1 and 2). Also supports logical block addressing (LBA) and
block transfers. ATA-2 is marketed as Fast ATA and Enhanced IDE
(EIDE). Also known as Ultra- DMA/0
ATA/33: Also called Ultra-DMA/2 , and DMA-33, supports
multiword DMA mode 3 running at 33 MBps.
ATA/66: or Ultra-DMA/4 A new version of ATA
proposed by Quantum Corporation, and supported by Intel, that will
double ATA's throughput to 66 MBps. Other ATA supports speeds of 100
ATA/100 aka Ultra-DMA/5
ATA/133 aka Ultra-DMA/6 currently the fastest IDE
hard drive in the market
Note if you do choose to have a hard drive that supports 66MB/s and
higher you will need to use an 80pin ribbon cable
instead of the traditional 40pin ribbon cable which
only supports 33MB/s.
Hard Drive Geometry
LBA Short for logical block addressing, a method used with
SCSI and IDE disk drives to translate the cylinder, head, and sector
specifications of the drive into addresses that can be used by an
enhanced BIOS. LBA is used with drive's that are larger than 504MB.
cyl * 16 heads * 63 sectors/track * 512 bytes/sector = 504MB
Short for Cylinders, Heads and Sector translation
Extended CHS a competitior to LBA supports different translation
1,024 cyl * 256 heads * 63 sectors/track * 512 bytes/sector = 8.4GB
Interrupt 13 extensions developed by Phoenix technology to support
up to 137GB
when installing hard drives it is best to set it to AUTO
detect mode in the CMOS/BIOS setup
DEFRAG A DOS and Windows utility that defragments your hard
disk. In Windows 95, you run Defrag by selecting Start->Programs->Accessories->System
SCANDISK A DOS and Windows utility that finds different types
of errors on hard disks and is able to correct some of them. In DOS,
you run Scandisk by entering scandisk at the prompt and pressing the
Enter key. In Windows 95, you can run Scandisk by selecting Start->Programs->Accessories->System
Among other things, Scandisk checks the disk platters for defects
and also looks for lost clusters that are sometimes created when a
Windows 2K/XP go to start>run>cmd and type CHKDSK
from the command prompt
FAT or File Allocation Table A table that the operating system
uses to locate files on a disk. Due to fragmentation, a file may be
divided into many sections that are scattered around the disk. The
FAT keeps track of all these pieces.
In DOS systems, FATs are stored in hidden files, called FAT files
The FAT system for older versions of Windows 95 is called VFAT,
and the one for new versions of Windows 95 and Windows 98 is called
FAT32. A new version of the file allocation table (FAT) available
in Windows 95 OSR 2 and Windows 98. FAT32 increases the number of
bits used to address clusters and also reduces the size of each cluster.
The result is that it can support larger disks (up to 2 terabytes)
and better storage efficiency (less slack space).
technology file system use in Windows 2K/XP/NT
environment for security support
Steps in installing a hard drive
1. Buy a hard drive usually look for space in terms of GB example
a 40 GB hard drive, the RPM/s usually 7200 or more is the revolution
per minute and the speed of the hard drive EIDE vs. Ultra DMA/33 which
is faster. Several vendors to consider when buying a hard drive include
Maxtor, Seagate, IBM, Western Digital, Fujitsu and Quantum.
2. Back up your computer and record settings like CMOS and desktop
settings before installing the hard drive.
3. Set jumper settings of master and slave, example if one hard drive
and CD/ROM were daisy chained on one 40-pin ribbon cable then the
jumper settings would be master on the hard drive and slave on the
CD/ROM. You can set jumper settings by looking at the back of the
hard drive and CD/ROM and follow the master and slave specification
4. Install 40 pin ribbon cable to hard drive making sure pin one which
is the red section is closest to the Molex power connector and install
other side to IDE controllers.
5. Install the Molex power connector from power supply to hard drive
for power if it's a PATA if a SATA hard drive install the 15 pin black
to CMOS setup and configure hard drives using the AUTO detect or manual
7. Partition hard drive, which is dividing hard drive into sections.
You can either use the DOS utility FDISK or use a 3rd party software
like PQ Magic to partition your drive. Usually the first partition
is the Primary partition. Set it to active in order for the OS to
boot up. That which is left over on the hard drive will become the
extended partition. Finally, divide the extended partition into logical
Example: if the hard drive has total space of 4GB, the primary partition
under FAT16 will be 2GB, which is the most you can allocate per hard
drive. The left over is the extended partition, which is 2GB. To get
this figure, Subtract 4GB total space minus the 2GB max in FAT16 and
you have 2GB left. Then divide the extended partition to logical partition,
in this case we will divide by 2, which leaves 1GB of D drive and
1GB of E drive. Under FAT32 large disk support is enabled and can
partition hard drives into the highest number so if you have a 40GB
hard drive you can partition that to the full 40GB max.
8. High-level Format each partition drive. This will make your partition
9. Install a file system FAT16, FAT32 and NTFS, the latter being used
for security with the drives.
10. Install and load the Operating System