03-08-2012, 02:58 PM
Seminar on Hard Disks
[attachment=30068]
Low-level format- organizes both sides of each platter into tracks and sectors to define where items will be stored on the disk.
Partitioning: divide hard disk into separate areas called partitions; each partition functions as if it were a separate hard disk drive.
High-level format defines the file allocation table (FAT) for each partition, which is a table of information used to locate files on the disk.
Storage Systems
Hard Drives
2 Types: SCSI and IDE
IDE drives-
originally developed as alternative to more expensive SCSI drives.
Modern versions called EIDE drives.
Support up to 4 multigigabyte drives.
If you want more devices, use SCSI or USB
Low-level formatted at the factory
Low Level Formatting
Low level format scans disk for defects and sets aside sectors with defects so they are not used for data.
IDE drives should never be low level formatted by a user or technician. Only high level format necessary.
Floppies
Two sizes
3.5 inch
5.25 inch
3.5 inch holds 1.44 MB for High density and 750 KB for Double Density
Connected with 34 pin ribbon cable
Two Floppy Drives possible
Has twist in cable to distinguish A drive from B drive
SCSI
Pronounced Scuzzy
Small Computer Systems Interface
For wide range of peripheral devices, including hard disks, tape drives, optical drives, CD-ROMs and disk arrays.
8 devices can connect to a daisy chain
This chain must be terminated at both ends
Each device on chain is assigned unique device ID number that is determined by jumpers or DIP switches
How Data is Organized on Disk
Tracks-
circular areas of the disk
Length of a track one circumference of disk
Over 1000 on a hard disk
Data first written to outer most track
Sectors-
Divides tracks sections
On a floppy 9 sectors exits
Cylinders-
Logical groupings of the the same track on each disk surface in a disk unit
Clusters-
Groups of sectors used by operating system
64 sectors in one cluster
[attachment=30068]
Low-level format- organizes both sides of each platter into tracks and sectors to define where items will be stored on the disk.
Partitioning: divide hard disk into separate areas called partitions; each partition functions as if it were a separate hard disk drive.
High-level format defines the file allocation table (FAT) for each partition, which is a table of information used to locate files on the disk.
Storage Systems
Hard Drives
2 Types: SCSI and IDE
IDE drives-
originally developed as alternative to more expensive SCSI drives.
Modern versions called EIDE drives.
Support up to 4 multigigabyte drives.
If you want more devices, use SCSI or USB
Low-level formatted at the factory
Low Level Formatting
Low level format scans disk for defects and sets aside sectors with defects so they are not used for data.
IDE drives should never be low level formatted by a user or technician. Only high level format necessary.
Floppies
Two sizes
3.5 inch
5.25 inch
3.5 inch holds 1.44 MB for High density and 750 KB for Double Density
Connected with 34 pin ribbon cable
Two Floppy Drives possible
Has twist in cable to distinguish A drive from B drive
SCSI
Pronounced Scuzzy
Small Computer Systems Interface
For wide range of peripheral devices, including hard disks, tape drives, optical drives, CD-ROMs and disk arrays.
8 devices can connect to a daisy chain
This chain must be terminated at both ends
Each device on chain is assigned unique device ID number that is determined by jumpers or DIP switches
How Data is Organized on Disk
Tracks-
circular areas of the disk
Length of a track one circumference of disk
Over 1000 on a hard disk
Data first written to outer most track
Sectors-
Divides tracks sections
On a floppy 9 sectors exits
Cylinders-
Logical groupings of the the same track on each disk surface in a disk unit
Clusters-
Groups of sectors used by operating system
64 sectors in one cluster