KarbosGuide.com. Module 6
About file systems: DOS formatting, FAT, etc.
The contents on this page:
We have seen before that the PC is a big data processor. We have also seen
that data are bits and bytes, which are organized in files. One of the
operating system's major tasks is to write these data to a disk. Hard,
floppy, and zip disks must be formatted before we can save files on them.
In these pages, we will review formatting, file systems, etc. We will start
with a general view, then go in depth about FAT formatting, which is (still)
the most common.
As I wrote in module 4a, drives are storage media, which
can hold a file system. When a disk is formatted in a drive, it becomes
organized and prepared to receive data. When we format a disk, it receives
a file system
Formatting can be compared to starting a library. You must install the
book shelves and the catalogue system before any books are put in place.
Once the library is ready, bring on the books! Similarly with a disk. When
we format it, we "burn in" a file system to make it ready to receive data
We can format with any one of several different file systems:
File Allocation Table
is the original, old 16 bit DOS system
is probably used in 90% of all PC’s. It is also called FAT16 contrary to:
This is a new addition to FAT, which Microsoft introduced
with Windows 95 B – the December -96 version (OSR2). The performance has
been even improved with Windows 98.
High Performance File System
is from OS/2. It is an advanced
32 bit file system, which in all respects is far superior to FAT, except
for possible usage. It can only be used with OS/2.
NTFS from Windows NT
A 32 bit file system like HPFS, but not
with it. NTFS can only be used in Windows NT/2000/XP. If it was
available for use in Windows 95/98, it may be preferable
to FAT and FAT32.
NetWare is a server operating system from Novell. It has its own 32 bit
file system. For that reason, the Novell server, contrary to NT or OS/2
servers, cannot be used as a work station. The file system is much faster
than FAT, but it works only with Novell servers (typically file servers).
This is for CDROMs and ISO 13346 for DVDs.
Universal Disk Format
is for big capacity disks like DVD
RAM. UDF is not directly supported by older versions of Windows , you need a driver.
UNIX servers have their own filing system. Here the use of upper/lower
case in file naming is significant.
Read in the following pages about the concepts of these file systems.
Relationship between file system and operating system
We see that that the file system is an integral part
of the operating system. An operating system can sometimes work with different
||FAT16, FAT32, NTFS
||proprietary file system|
The file system is actually the interface between operating
system and drives. When the user software, such as MS Word, asks to read
a file from the hard disk, the operating system (Windows 95/98 or NT) asks
the file system (FAT or NTFS) to open the file:
The file system knows where files are saved. It finds and reads the
relevant sectors and delivers the data to the operating system.
Limitations in disk size
Over the years, the PC has suffered from a long list
of irritating limitations. The hard disk industry has continuously developed
hard disks with increasing capacity. However, the system software (BIOS,
DOS, and FAT) has set its limitations:
DOS versions below 3.0 could only handle hard disks up to 16 MB.
Versions 3.0 to 3.32 could handle up to 32 MB.
DOS 4.0 could handle up to 128 MB.
DOS version 5.0 and the BIOS, which controls IDE drives, could only accept
1024 cylinders and disks up to 528 MB. This limit was broken with the EIDE
FAT16 can handle a maximum of 2 GB because of 16 bit calculations of the
FAT32 accepts disks up to 2048 GB. This standard will probably last another
couple of years.
Let us return to the file system in next page.
Read Windows tipswith a little
about Windows 95/98.
Read Module 6c about the relationship
between BIOS, OS and hardware
Read Module 7a about the videosystem
Read about video cards in Module 7b .
Read about digital sound in Module 7c .
Copyright (c) 1996-2005 by Michael B. Karbo. www.karbosguide.com.