Partitioning Hard Drives

Disk Organization MBR tells layout of the disk Primary PartitionExtended Partition Logical Drives

Use of partitions All OSs do NOT have the same rules for partitioning MBR contains a layout of the partitioning info Primary Partition is always there –may consume all space –i.e. no Extended Partition Extended Partition needs to be sub-allocated –numerous logical drives possible –may have different OSs … more later

Drive Naming (DOS) MBR tells layout of the disk Primary PartitionExtended Partition Logical Drives Assuming no other drives and only DOS C: D:E:F:

Primary, Extended, Logical DOS was only programmed to see one normal partition. All other “partitions (logical drives)” had to be enclosed in an Extended partition Other OSs such as linux do not require an extended partition but can see and use them

2 Drives (DOS) MBR tells layout of the disk Primary PartitionExtended Partition Logical Drives C: E:F: MBR tells layout of the disk Primary PartitionExtended Partition Logical Drives D: G:H: Master Slave

How Do You Partition? The OS has a program called “fdisk” Linux and DOS both have fdisk and have varying degrees of compatibility. Linux sees DOS –will let you create DOS partitions DOS sees Linux as Non-Dos. –Will not create Non-Dos

Using DOS fdisk Create primary partition Create extended partition if necessary Create logical partitions within extended Exit fdisk and reboot Format each of the drives Be sure to make the primary partition bootable ( format c: /s )

Multi-booting machines Using more than one OS on the same machine The MBR also tells the BIOS which partition to boot from. Different OSs use different boot loaders so they may periodically need to be reset –(fdisk /mbr) Some boot loaders (DOS) only allow for booting their OS. E.g. DOS.

Multi-booting machines (ctd) Linux lets you choose –lilo –grub Some boot loaders have funny restrictions –boot partition must be on master drive –boot partition must be in first 1024 cylinders –most newer ones do not have those restrictions can boot from any partition

Multibooting (funny) MBR tells layout of the disk Primary DOS Partition Extended Partition Logical Drives C: NonDosD:E: Non Dos 1024 cyl

Why partition? OS may not support a logical drive as big as your disk; make the physical drive multiple logical drives. BIOS has it’s limitations too! May not want all of the disk to expire at the same time (system versus user space) Multiple OSs on the same disk (multi-boot) Different permissions/access Different File systems

Can you alter after loading files? Yes, but not a trivial process Typically these applications are available. Some freeware.. Some not Available in linux and DOS/windows Partition Magic is a good program that supports linux and windows file systems Typically reboot from a floppy while changing

How much space? Always depends on the question.. What are you going to store on it? Multiboot –Windows 98 needs >1G for bare installation –linux needs >1G depending on installation linux only –installation program will optimize allocation if you let it to handle the problem of preserving system space as needed.

Booting UP Bootloader determines which OS is used –lets you manually override –may boot with floppy to override BIOS has MORE control –which drive first CDROM (installations) Hard Drive - Typically Floppy - To override hard drive