The Linux Convert - moving from closed to Open Source

Essential Items - The Hard Disks.

So far things are going well and its time for our next decision. "What should we do about the hard disks?"

Before we go into it, a quick refresher on what they are and what we will do with them. The "hard disks" are the main data storage devices you have in your system. Unlike RAM, they retain their data when the machine is turned off. They store everything from the Operating System files, to user account details and the data you save in your programs. In addition to this, Linux makes excellent use of swap files, which again takes up more hard disk space. While the hard disks are not the most glamourous or talked about aspects of a machine, they are essential so lets look at our options.

As we want to use this machine for a wide variety of tasks we probably will need two disks and we can choose between SCSI and EIDE(also called ATA) interfaces. SCSI has the advantage of generally being faster and in the future we can add LOTS of extra drives, EIDE is limited to a maximum of four devices. However EIDE is a lot cheaper and in modern drives the speed difference is negligble (in fact, EIDE is now quite often faster). For our purposes EIDE will be more than acceptable, but we will invest in two disks - when it comes to actually installing, the decision can be made to have these as mirrored drives or simply span volumes across them.

Looking at the disks available on sites like Ebuyer or Dabs.com, and its immediately obvious there is a wide selection to pick from. For example on Ebuyer, they are listed in three categories, IDE, Serial ATA and SCSI. The IDE (our first choice) disks come in ranges of 40 Gb up to 250 Gb, Serial ATA are all in the 160-250 Gb range and SCSI range from 18 Gb to 300 Gb (!!).

Although we could go for the largest disks, with a Linux machine it is better to have several disks and mount separate partitions on each - for example one for system files and one for data/user files. Basically it is very unlikely that both disks will go down at the same time, which will allow you to either preserve the users data while you either repair or replace the system disk or if the user disk dies then you still have a functioning system to restore the backups.

In order to determine the size you will need, consider what you will use the machine for: current Linux distros are massive - they include gigabytes of application software and source code. If you are building your own PC you need to decide just how much you want to install. For the majority of users a full install will take up less than 8Gb, you want to allocate 512mb to swap file, give each user a disk quota in the region of 2Gb, have 10Gb spare as a backup partition. This will allow you to "guestimate" the size of disk (or disks) you need.

For the purposes of this project we will require the following space:

• Base Installation of Linux (inc apps and source code) ~ 9 Gb
• Swap File - 1 Gb
• Ten user accounts - 20Gb
• Video Editing space - 40 Gb
• Back up partition ~ 9 Gb

As you can see, we will need at least 80 Gb hard disk space, ideally two 80+ Gb drives. Back to our web browsers.... Now its time for some maths. Look at the drives that interest you and work out the "cost per Gb" - that way you can easily compare different sized drives based on cost.

With 80 Gb as our minimum and ideally two disks for under £100, one of the better options appears to be the Hitatchi Deskstar drives. Both Ebuyer and Dabs have these available for £32-36.99 (Dabs is cheaper but its a "special offer" price). This means, getting two of these disks will dent our budget by £73.98. This leaves us with £535.10 left in the bank.