4mb Laptop HOWTO

2. The Laptops

This section describes the laptops that I have used this procedure on, the problems faced when installing Linux on them and the solutions to those problems (in outline).

2.1 Basic Specifications

Compaq Contura Aero

• 25MHz 486SX CPU
• 4mb RAM
• 170mb Hard Disk
• 1 PCMCIA Type II slot
• External PCMCIA 3.5" Floppy drive

  The PCMCIA floppy drive has a proprietary interface which is partly handled by the Aero's unique BIOS. The Linux PCMCIA drivers can't work with it. According to the PCMCIA-HOWTO, if the drive is connected when the laptop boots it will work as a standard drive and Card Services will ignore the socket but it is not hot-swappable. However, I found that the drive becomes inaccessible as soon as Card Services start unless there is a mounted disk in the drive. This has implications for the installation process - these are covered at the relevant points.

Toshiba T1910

• 33MHz 486SX CPU
• 4mb RAM
• 200 mb Hard Disk
• Internal 3.5" Floppy drive
• 1 PCMCIA Type II/III slot

2.2 The Problem

The small hard disks and the lack of an internal floppy on the Aero make the installation more tricky than normal but the real problem is the RAM. None of the current distributions has an installation disk that will boot in 4mb, not even if the whole hard disk is a swap partition.

The standard installation uses a boot disk to uncompress a root-partition image (either from a second floppy or from CD-ROM) into a ram-disk. The root-image is around 4mb in size. That's all the RAM available in this scenario. Try it and it freezes while unpacking the root-image.

2.3 The Solution

The answer is to eliminate the ram-disk. If you can mount root on a physical partition you will have enough memory to do the install. Since the uncompressed ram-disk is too big to fit on a floppy, the only place left is on the hard disk of the laptop. The steps are:

1. Find something that will boot in 4mb ram and which can also create ext2 partitions.
2. Use it to create a swap partition and a small ext2 partition on the laptop's hard disk.
3. Uncompress the installation root-image and copy it onto the ext2 partition.
4. Boot the laptop from the installation boot-disk, pointing it at the ext2 partition on the hard disk.
5. The installation should go more or less as normal from here.

The only question was whether a distribution that wouldn't install (under normal circumstances) on the laptops would run on them. The short answer is "Yes".

If you're an old Linux hand then that's all you need to know. If not, read on - some of the steps listed above aren't as simple as they look.