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Some of the most commonly used terms assosiated with
HDD
Platter
A rigid disk that serves as an individual component of a hard disk. Hard disks usually consist of several stacked
platters. The platters are coated with magnetic media, allowing them to store data as localized changes in magnetic
polarity.
Cluster
The basic allocation unit of magnetic disks storage. Clusters (also known as allocation units) consist of one or
more disk sectors. Because storage space is allocated based on clusters, even if a file (or part of a file) physically
occupies only a portion of a cluster, that entire cluster will be allocated to the file, and will be considered
used disk space. Since file sizes are only rarely exact multiples of the cluster size, the last cluster storing
the file's data usually includes some empty space called "slack space" at the end. Clusters make it possible
for the operating system to manage the files on a disk more effectively than it could if it had to work at the
sector level.
Sector
An arc-shaped portion of the data storage area of a disk that is the smallest physical storage unit of the disk.
Disk storage area is organized into:
- Sides of the disk surface (top and bottom) A
hard disk may have more than two sides if it consists of more than one platter.
- Tracks, which are arranged as concentric rings
on the surface of magnetic disks. CD-ROMs have a single track, spiraling from the disk edge towards the center.
- Sectors, which occupy arc-shaped portions of
the tracks.
One sector of data storage occupies an arc-shaped portion of one of the disk tracks.
The operating system determines the size of each sector, which is 512 bytes (Microsoft has decided in making
4K the default cluster size for FAT32) for magnetic disks formatted for US versions of Windows.
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Inside The Hard Disk
SOME OF THE COMPONENT HEADERS HAVE CLICKABLE LINKS FOR MORE DETAILS !
Image Map Links:
| + Actuator Arm
| + Head Slider - Arms - Actuator | +
Platters |
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HARD DISK
Terminology as used in CONFIGURING a drive in CMOS
Setup
CYLINDERS
Like tracks, the number of concentric cylinders upon which data is recorded, typically 300 to 3000.
SECTORS
Number of pie shaped wedges each track is divided into typically 8 to 64.
HEADS
Number of sides of magnetic material available to record on and hence number of read/write heads in the disk drive
typically 2 to 256.
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FORMULA TO CALCULATE HDD CAPACITY
Use the following formula to calculate the capacity of the hard disk drive.
Bytes per sector 512 x number of cylinders 3736 x number of heads 255 x 63 sectors
Calculation example for Maxtor 33073H3 capacity.
| |
| Bytes per Sector |
=
|
512
|
| Cylinders |
=
|
3736
|
| Heads |
=
|
255
|
| Sectors |
=
|
63
|
|
| |
|
| |
| 1. |
512 bytes x 3,736 cylinders |
=
|
1,912,832
|
| 2. |
255 heads x 63 sectors |
=
|
16,065
|
| 3. |
16,065 x 1,912,832 |
=
|
30,729,646,080
|
|
512 bytes x 3,736 cylinders x 255 heads x 63 sectors = 30,729,646,080 bytes
30,729,646,080 bytes ÷ 1024 = 30,009,420 KB ÷ 1024 = 29306.07421875 MB ÷
1024 = 28.619213104248046875 GB
Approximately ~ 28 GB when using binary
1024 as the measure.
This same 30 GB hard disk is 30,000 MB = 30 GB when using decimal 1000 as the measure.
You get the exact numbers from the sticker attached to
the HDD or from the manufacturers specifications. You should then use those numbers in the calculation to get the
capacity.
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FORMATTING
Formatting Definitions:
- To divide (a disk) into marked sectors so that it may store data.
- To determine the arrangement of (data) for storage or display.
-Strictly, formatting is organising and marking the surface of a disk into tracks, sectors , and cylinders. It
is also sometimes (incorrectly) a term used to signify the action of writing a filesystem to a disk (especially
in the MS Windows/MS DOS world).
- The act of writing a filesystem on a disk drive.
- Preparing a disk to receive data. Formatting software organizes a disk into logical units, like blocks, sectors,
and tracks.
- The process of organizing a disk so that it is usable in a particular operating environment.
So, do get through the following and determine by Yourselves the act of formatting the HDD...
1. Low-Level Formatting
This type of formatting writes normally zeros on the hard disk thus over-writing everything on the HDD and it also
destroys any partitions. You should get a low-level formatting utility or a zero-fill utility from the HDD manufacturers'
web site.
Low-level formatting is the process of outlining the positions of the tracks and sectors on the hard disk, and
writing the control structures that define where the tracks and sectors are. This is often called a "true"
formatting operation, because it really creates the physical format that defines where the data is stored on the
disk. The first time that a low-level format ("LLF") is performed on a hard disk, the disk's platters
start out empty. That's the last time the platters will be empty for the life of the drive. If an LLF is done on
a disk with data on it already, the data is permanently erased and lost.
2. High-Level Formatting
This type of formatting prepares the HDD for an Operating System.
After low-level formatting is completed, the disk is only with tracks and sectors and nothing written on them.
High-level formatting is the process of writing the file system structures on the disk that let the disk been used
for storing programs and data. If you are using DOS, for example, the DOS FORMAT command performs this work, writing
such structures as the master boot record and file allocation tables to the disk. High-level formatting is done
after the hard disk has been partitioned, even if only one partition is to be used.
Formatting Notes
The distinction between high-level formatting and low-level formatting is important. It is not always necessary
to low-level format the hard disk to erase and clean it. High-Level Format is good for Operating System re-constructive
purposes or HDD data management. High-Level Formatting is done by wiping out the control structures and writing
new ones, so that the old information seems to be lost and the disk appears as new. Most of the old data is still
on the disk, but the access paths to it have been wiped out. This deleted data remains recoverable at all the times
until HDD has been filled to the point that the old data is automatically over-written with the new data.
Under certain circumstances such as viruses, Trojans, software marked bad sectors, just to mention some, a high-level
format won't fix problems. Low Level Formatting is needed to clean and destroy the remaining data that is left
behind on the hard disk.
Different operating systems use different high-level format programs, because they use different file systems.
However, the low-level format, which is the real place where tracks and sectors are recorded, is the same.
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PARTITIONING
After a drive is physically installed and CMOS is setup to identify it (for IDE types only, not required for SCSI
drives), FDISK must be run to partition the drive even if you only want one large partition.
The FDISK utility allows you to:
1. Partition the disk into any number of logical drives for example, 40 GB drive may be partitioned into two 20
GB drives (C: and D:) and with specific cluster sizes (the larger the partition the bigger the cluster size if
not formatted with cluster size switch specified by the user).
2. Assign an ACTIVE partition to the boot drive (usually C:)
The drive partition containing the operating system must be made "ACTIVE" in order to load from it upon
boot-up. See more about partitioning at the section Partitioning the Hard Disk.
Hard Disk Drive size is sometimes informed bigger by the manufacturers than the operating system scan disk verification
confirms; converting between binary gigabytes and binary megabytes. Decimal gigabytes and megabytes differ by a
factor of 1,000 but of course the binary measures differ by 1,024. So this same 30 GB hard disk is 30,000 MB in
decimal terms. But its 27.94 binary gigabytes are equal to 28,610 binary megabytes (27.94 times 1,024).
|
1000 bytes = 1 KiloByte | 1000 KB =
1 MegaByte | 1000 MB = 1 GigaByte
|
|
1024 bytes = 1 KiloByte | 1024 KB =
1 MegaByte | 1024 MB = 1 GigaByte
|
There's potential good news regarding this whole binary/decimal
confusion. The IEEE has proposed a new naming convention for the binary numbers. Under this proposal, for binary
numbers the third and fourth letters in the prefix are changed to "bi", so "mega" becomes "mebi"
for example. Thus, one megabyte would be 10^6 bytes, but one mebibyte would be 2^20 bytes. The abbreviation would
become "1 MiB" instead of "1 MB". Summary table showing the decimal and binary measurements
and their abbreviations and values ("bytes" are shown as an example unit here, but the prefices could
apply to any unit of measure):
|
Decimal Name
|
Decimal Abbr.
|
Decimal Power
|
Decimal Value
|
|
Kilobyte
|
kB
|
10^3
|
1,000
|
|
Megabyte
|
MB
|
10^6
|
1,000,000
|
|
Gigabyte
|
GB
|
10^9
|
1,000,000,000
|
|
Terabyte
|
TB
|
10^12
|
1,000,000,000,000
|
|
Binary Name
|
Binary Abbr.
|
Binary Power
|
Binary Value
|
|
Kibibyte
|
kiB
|
2^10
|
1,024
|
|
Mebibyte
|
MiB
|
2^20
|
1,048,576
|
|
Gibibyte
|
GiB
|
2^30
|
1,073,741,824
|
|
Tebibyte
|
TiB
|
2^40
|
1,099,511,627,776
|
FAT-issues:
To quote the Microsoft Knowledge Base article referenced below:
"For most users, FAT32 will have a negligible performance impact. Some programs may see a slight performance
gain from FAT32. In other programs, particularly those heavily dependent on large sequential read or write operations,
FAT32 may result in a modest performance degradation."
FAT32 does NOT affect system performance.
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Cluster Size
Basically, the more clusters on your hard drive, the slower the performance. This is true for any file system,
FAT16, FAT32, NTFS, HPFS, whatever. However, since FAT32 allows for many more clusters on a single partition than
FAT16, the effect may be noticable. Disk utilities are especially affected (slower) the more clusters in the partition.
For instance, the closer to 8GB your partition gets, the more 4K clusters, and the slower the performance. (However,
as your partition gets bigger, your slack vs. FAT16 improves.)
In preliminary benchmark testing, FAT32 and FAT16 benchmark roughly the same (within 2% either way) when partition
size and cluster size are the same. (Note that in order to create a FAT32 partition with the same cluster size
as FAT16, the /Z switch must be used when formatting.) However, when cluster sizes are made smaller and the number
of clusters increases (only possible with FAT32), disk performance degrades.
Thus there is a battle between slack and performance: Small clusters mean less slack but worse performance.
Large clusters mean more slack but better performance. Most users will notice slack differences much more
than performance differences caused by varying cluster sizes. Microsoft has decided for us (in making 4K the default
cluster size for FAT32) that 4K clusters is the best balance between slack and performance. However, with the /Z
switch on the FORMAT command, the user has the ability to decide for his/herself what cluster sizes should be,
based on the user's concerns about slack vs. performance.
Read the table below for choosing the cluster size on basis of disk size for better performance and limiting slack
space.
Best recommended Cluster size for your drive
| Disk Size |
Cluster Size Recommended |
Format Command Option* |
| Less than 1 GB |
4 KB
|
Format x: |
| Less than 4 GB |
8 KB
|
Format x: /z:16 |
| Between 4 to 32 GB |
32 KB **
|
Format x: /z:64 |
*x: is the drive i.e. e.g. for c drive it is format
c:
**32 KB Cluster Size is best for performance, even faster than FAT16. Test drive runs on FAT32 with cluster
size of 4 KB(4096bytes) and System Information by Norton Utilities 4.0 gives the cached read/write benchmark of
102.7 MB and 53.3 MB physical read/write speed respectively on 30GB Maxtor 33073H3.
Abbreviations used in the following data-tables:
| ATA |
AT attachment |
|
MB |
megabyte |
| bpi |
bits per inch |
|
Mbits/sec |
megabits per second |
| CHS |
cylinder - head - sector |
|
MB/sec |
megabytes per second |
| db |
decibels |
|
MHz |
megahertz |
| dbA |
decibels, A weighted |
|
ms |
millisecond |
| DMA |
direct memory access |
|
MSB |
most significant bit |
| ECC |
error correction code |
|
mV |
millivolts |
| fci |
flux changes per inch |
|
ns |
nanoseconds |
| G |
acceleration |
|
PIO |
programmed input/output |
| GB |
gigabyte |
|
RPM |
revolutions per minute |
| Hz |
hertz |
|
tpi |
tracks per inch |
| KB |
kilobyte |
|
UDMA |
ultra direct memory access |
| LBA |
logical block address(ing) |
|
µsec |
microsecond |
| LSB |
least significant bit |
|
V |
volts |
| mA |
milliamperes |
|
W |
watts |
Sources: Symantec Corp., Microsoft, Maxtor, IBM, KEPCIL
Designs.
| Hard disk drive: |
30GB Maxtor 33073H3 |
| Firmware: |
YAH814Y0 |
| Hard disk drive size: |
3.5 in |
Performance Specifications
| MAXTOR MODELS |
34098H4 | 33073H3 | 32049H2 | 31024H1
|
| Seek Times (typical read) |
| Track-to-Track |
1.0 ms |
| Average (performance) |
9.5 ms |
| Average (silent mode) |
15 ms |
| Full Stroke |
< 20.0 ms |
| Average Latency |
5.55 ms |
| Rotational Speed (+ 0.1%) |
5400 RPM |
| Controller Overhead |
< 0.3 ms |
Data Transfer Rate
To / From Interface
(Ultra ATA / 100, DMA - M5) |
up to 100 MBytes / sec. |
To / From Interface
(P IO 4 / Multi-word DMA M5) |
up to 16.7 MBytes / sec. |
| To / From Media |
up to 46.7 MBytes / sec. |
| Start Time (0 to Drive Ready) |
8.5 sec. typical |
Drive Configuration
| MODEL |
Maxtor 33073H3 |
| Integrated Interface |
ATA-5 / Ultra ATA/100 |
| Encoding Method |
E2 PR4 RLL 16/17 |
| Interleave |
1:1 |
| Servo System |
Embedded |
| Buffer Size / Type |
2 MB SDRAM |
| Data Zones per Sur face |
16 |
| Data Surfaces / Heads |
3 |
| Number of Disks |
2 |
| Areal Density |
14.7 Gbits / in2 max |
| Track Density |
34 000 tpi |
| Recording Density |
354 to 431 kbpi |
| Bytes per Sector / Block |
512 |
| Sectors per Track |
373 to 746 |
| Sectors per Drive |
60 032 448 |
Performance Specifications
| MODEL |
Maxtor 33073H3 |
| Seek Times (typical read) |
|
| Track- to-Track |
1.0 ms |
| Average (performance) |
9.5 ms |
| Average (silent mode) |
15 ms |
| Full Stroke |
<20.0 ms |
| Average Latency |
5.55 ms |
| Rotational Speed (±0.1%) |
5400 RPM |
| Controller Overhead |
< 0.3 ms |
| Data Transfer Rate |
|
| To/From Interface (Ultra ATA/100, DMA - M5) |
up to 100 MBytes/sec |
| To/FromInter face (P IO 4/Multi -word DMA M5) |
up to 16.7 MBytes/sec |
| To/From Media |
up to 46.7 MBytes/sec |
| Start Time (0 to Drive Ready) |
8.5 sec typical |
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About diagnosing and fixing problems
I am using Symantec Norton Utilities to "keep my computer running". It has disk utilities to test, diagnose
and repair hard disk errors. Trouble-free computing depends on the integrity of your computer, which requires an
error-free hard disk and a correctly installed copy of Windows. The trouble is, although most computers start out
this way, over time Windows and hard drives are likely to degrade. This degradation, if not corrected, can ultimately
lead to data loss. The best cure for any problem is prevention. Many Norton Utilities programs are on alert for
the most common error conditions that can cause computer lock-ups and crashes, and in turn lead to computer problems
and data loss. If a Norton Utilities program detects a potential problem, it can correct the condition automatically,
or warn you, giving you the option to fix the problem if possible.
Well, actually I have downloaded some other additional utilities, such as EasyCleaner from ToniArts, SpyBot's Search
& Destroy and of course always doing the old way, manually checking and cleaning the registry with Windows
Registry Editor which I prefer the most. Anyway, nowadays there are many "background" programs that are
affecting the overall performance of the hard disk. You should manually configure your programs to give permit
to access the hard disk resources while another program is running.
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Sample Test Result:
Disk Doctor
Norton Utilities for Win95
June 26, 2001 8:52am
*************************
* Report for Drive C: *
*************************
DISK TOTALS
----------------------------------------
6,000,128 kilobytes Total Disk Space
1,690,210,304 bytes in 13,426 User Files
4,349,952 bytes in 987 Directories
15,572,992 bytes in 691 Hidden Files
4,318,208 kilobytes available on the disk
LOGICAL DISK INFORMATION
----------------------------------------
Media Descriptor: F8
Large Partition: Yes
FAT Type: 32-bit
Total Sectors: 12,000,492
Total Clusters: 1,497,132
Bytes Per Sector: 512
Sectors Per Cluster: 8
Bytes Per Cluster: 4,096
Number of FATs: 2
First Sector of FAT: 32
Number of Sectors Per FAT: 11,700
First Cluster of Root Dir: 2
Number of Clusters in Root Dir: 1
First Sector of Data Area: 23,432 |
PHYSICAL DISK INFORMATION
----------------------------------------
Drive Number: 80
Heads: 255
Cylinders: 3,736
Sectors Per Track: 63
Starting Head: 1
Starting Cylinder: 0
Starting Sector: 1
Ending Head: 254
Ending Cylinder: 746
Ending Sector: 63
SYSTEM AREA STATUS
----------------------------------------
No errors in the system area
FILE STRUCTURE STATUS
----------------------------------------
No errors in the file structure
FREE SPACE STATUS
----------------------------------------
No errors in the free cluster count
SURFACE TEST STATUS
----------------------------------------
Test Settings
-----------------------
Test: Entire Disk Area
Test Type: Normal Test
Repair Setting: Prompt before Repairing
Passes Requested: 1
Passes Completed: 1
Elapsed Time: 16 minutes, 7 seconds
No errors encountered in Surface Test |
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