Page 349 - FUNDAMENTALS OF COMPUTER

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NPP Memory 349

high. It is 3600 RPM and higher. The Number _| aIm OmVm h¡Ÿ& BZH$s Ky_Zo H$s J{V AË`{YH$ hmoVr
of tracks per surface and sectors per track are h¡ Ÿ& `h J{V 3600 RPM `m A{YH$ hmoVr h¡ Ÿ& Bg_|
higher. Bits per inch is also higher. Hard disks à{V gVh na Q´>oH$m| H$s g§»`m, à{V Q´>oH$ _| goŠQ>am| H$s
are available in different physical sizes as 3.5
inch, 5 inch and 8 inch. Since the disk is sealed g§»`m, à{V B§M _| {~Q>m| H$s g§»`m Am{X Ho$ H$maU BZH$s
in airfree and dust free environment, chances j_Vm A{YH$ hmoVr h¡Ÿ& `o {d{^Þ ^m¡{VH$ AmH$mam| _| ^r
of damage are also reduced. Since the informa- CnbãY h¢ : 3.5, 5 VWm 8 B§MŸ& My±{H$ {S>ñH$ H$mo {Zdm©V
tion is recorded on both surfaces, tracks per _| Yyba{hV H$aHo$ aIm OmVm h¡, Bg{bE BZHo$ Iam~ hmoZo
surface are greater, sectors per track are greater, H$s gå^mdZm H$_ hmoVr h¡Ÿ& H$åß`yQ>a _| gm_mÝ`V`m GB
bits per inch is large, the hard-disk capacity is VH$ H$s j_Vm H$s hmS>©{S>ñH$ bJr hmoVr h¡Ÿ& {XZ na {XZ
very large. For PC is it used in GB. Their capac-
ity is improving day by day. The transfer rate BZH$s j_Vm ~‹T> ahr h¡Ÿ& S>mQ>m Q´>m§g\$a H$s Xa ^r MB

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is of the order of MB/Sec. Reliability is 1 in à{V goH$ÊS> _| hmoVr h¢Ÿ& BgH$s {dídgZr`Vm 10 _|
11
10 . The disk pack and drive are enclosed in a 1 h¡Ÿ& `o {S>ñH$ ~ma-~ma hQ>mZo d bJmZo Ho$ {bE C{MV
single unit. The disks are not removable. Zht hmoVr h¢Ÿ&
4.6 Comparison of Floppy and Hard Disk
S. Floppy Disk Hard Disk
No.

1. Lower storage capacity. e.g. 1.2 MB, Large storage capacity, available in GB.
1.44 MB
2. Surface is flexible and thin, which is Surface is Hard and thick, made of Aluminium.
made of plastic.
3. One circular sheet is used only. Multiple number of platters are used.

4. Read-write head touches the surface Head is few µm above the surface.
5. More chances of wear and tear. Less chances of wear and tear (Damage).
6. Rotation speed is 300/360 RPM (Rota- Rotational speed is 3600 RPM and higher.
tion per minute).
7. Slower data transfer rate. Faster data transfer rate.
8. Floppy surface is open in atmosphere. Hard disk plates are vacuum sealed.
9. Floppy disk and FDC (Floppy disk con- Hard Disk and HDC are assembled in a single
troller) are separate units. unit.
10. May be single or double sided. Always double sided.
11. Easily Removable. Cannot be easily removed.
12. Cheaper. Expensive.
13. Can be write protected externally. Can be write protected with software.