Überhacker II, Chapter 3: How to
Get Many Operating Systems on One PC
In this chapter you will learn about:
· The BIOS
· Hard drives
· How to install more than
one IDE hard drive on a computer
· File systems
· The expensive but easy way
· The Partition Commander/System
· The SuSE Solution for Linux
plus Windows XP and 2000 all on the same drive
· How to make a triple
boot disk the harder way
· How to create a triple boot system
without boot magic or system commander
· Become a computer recycling
· Run virtual machines
at the same time on one computer
Why put a whole bunch of operating systems on one PC? I do it
to be able to reconfigure my network by rebooting its computers
to the operating systems needed for the experiments of the day.
Once upon a time this wasn't easy. Hard drives were small. The
BIOS (Basic Input/Output System) that is the heart of any PC used
to be designed for one, and only one operating system and only
tiny hard drives. Today's PCs make it super easy.
Word of warning: in this chapter you may want to do things to
the inside of your computer. Don't forget to use a grounding strap
and TURN THE COMPUTER OFF. Also, some computers (those that can
be turned on from across a LAN) leave power on to the motherboard
even when power is "off." So unless you are certain
your computer has no power to the motherboard, unplug it from
the power source.
Also, you may murder your operating system.
This chapter is not for sissies.
The most important part of your multiboot computer may be its
BIOS. It is usually kept in a PROM, EPROM, EEPROM or Flash ROM.
The BIOS configuration information is kept on a CMOS chip kept
powered up by a tiny battery. The BIOS is what tells your computer
on startup how to recognize and integrate all the components of
the system. For multiboot computers, the significant part of this
task is how it recognizes the floppy, CD/DVD whatever drives (most
BIOSes just call them cdroms), IDE (Integrated Drive Electronics)
and SCSI (Small Computer Systems Interface) hard drives, and how
it chooses from which one to boot the operating system.
Some BIOSes are too primitive to easily boot more than two or
three operating systems. Some, on older computers, won't even
allow you to install many operating systems unless you engage
in extreme measures. Here's to tell how good the BIOS is.
On bootup, the first thing you should see and remember is the
type of BIOS your computer runs. Next, look on the screen for
instructions on what key to hit (usually "delete") to
get into the BIOS setup. According to Tom Massey, "It can
be an F key, a combination of Ctrl, Alt, etc. Best to watch carefully
what's displayed on your monitor during bootup. Older machines
may not display the info you need to get into BIOS setup, so you
may have to do some tricky web searching, post to newsgroups and
On the settings for your hard drives, check to see if they let
you specify LBA (logical block addressing) or autodetect. If so,
you are in luck. This means you can use hard drives larger than
2.1 gigs. If not, and if you can't upgrade your BIOS to handle
LBA, forget about putting three operating systems on one hard
drive. You won't have enough space to do anything worthwhile,
and you are stuck with an ancient drive that is literally dying
to crash. However, that doesn't mean your wimpy old computer is
ready for the recycle bin.
Mike Orton has a solution:
The Big bear group, a small computer firm in Wales, UK, e-mail:
email@example.com, sells RAID cards for 13 UK pounds.
These will enable you to add up to four 120 Gig IDEs to a 486,
using its BIOS to run the HD's. It can be configured to run
like this, not as a proper RAID card. However I don't know how
well it works with several O/S on it
of course the 486
will be too slow for any MS system above Windoze 3.x But it
is another option if your BIOS won't run a large HD. There must
be sources in the USA and Europe.
Tom Massey has another solution: "Linux doesn't rely on
the BIOS to talk to hard drives. Stick the latest version of LILO
on your MBR (master boot record) and disk size isn't a problem."
However, Tanvir Ahmed says, "LILO is getting archaic. Redhat
does not support it anymore. GRUB seems to be the future and a
Regardless of whether your BIOS handles LBA, it is worth it to
get online and look up the web site of the manufacturer of your
BIOS. You may be in for a pleasant surprise. You may find that
the manufacturer will make it easy for you to upgrade your BIOS
to handle even larger hard drives. Now you will know whether that
tempting 100 Gig hard drive will be compatible with your computer.
Next, before you do anything else, look to see if your BIOS offers
virus protection. BIOS virus protection will cause your computer
to raise a fuss if the master boot record of any of your disks
is about to be modified. You are going to have to modify your
master boot record - many times - which will be much easier if
your BIOS isn't fighting you. If it is there, be sure to disable
If at all possible, get a computer that has a BIOS that will
let you boot from the drive of your choice. While LILO can be
helpful, if you are building a system that uses other means to
boot, this will make life much easier.
The ability to set the devices from which it can boot and the
order in which it looks for a bootable device is often under a
heading such as "BIOS features setup." You need to be
able to boot from the CD or DVD drive. A boot option of "cdrom"
will enable boot from a CD-ROM, CD-R, CD-RW or DVD drive. Installation
of most operating systems requires boot from "cdrom."
You can sometimes get around this by creating a boot floppy, but
it is painful.
If you have a choice, use a computer whose BIOS lets you choose
which IDE hard drive you boot by device name: IDE0, IDE1, IDE2,
IDE3. Choices of C, D, E, or F are a bad idea. If you partition
a hard drive, your operating system will have different drive
letter designations than your BIOS uses. This can create confusion
when you want to specify a boot disk.