Disk Images: Difference between revisions
| [unchecked revision] | [unchecked revision] |
m (added fat_imgen image generation utility) |
m (modified the URL for fat_imgen) |
||
| Line 81: | Line 81: | ||
|- |
|- |
||
| [http://trac.assembla.com/ambient/browser/fat_imgen fat_imgen] |
| [http://trac.assembla.com/ambient/browser/fat_imgen/branches/latest_stable fat_imgen] |
||
| {{Yes}} |
| {{Yes}} |
||
| {{Yes}} |
| {{Yes}} |
||
Revision as of 08:44, 28 October 2008
The best way for hobbyist os developers to test their systems is to use programs like QEMU, Bochs, VMWare or VirtualPC.
All of these common tools rely on using disk images (either floppy or hard disk). A disk image is nothing more than a file whose content reflects the layout of a disk and that the tool will use as if it was a physical device. E.g. A floppy image typically is 1.44MB large and its 512 first bytes consist of the 'floppy's boot sector. The different sub-pages should tell you how to create such images from real disks and use them under the most common operating systems.
Tools
These programs can help you with the management of disk images
| Linux | Windows | BSD | Mac OS X | File Systems Supported | |
|---|---|---|---|---|---|
| BFI | No | Yes | No | No | FAT |
| File Disk | No | Yes | No | No | Anything supported by Windows |
| hdiutil | No | No | No | Yes | HFS HFS+ HFS+J HFSX FAT UFS |
| Loopback Device | Yes | No | Yes | Yes | Anything supported by the kernel |
| mkisofs | Yes | Yes | Yes | Yes | ISO 9660 |
| MTools | Yes | Yes | Yes | Yes | FAT |
| Virtual Floppy Disk | No | Yes | No | No | Anything supported by Windows |
| Win Image | No | Yes | No | No | FAT ISO 9660 |
| fat_imgen | Yes | Yes | Yes | Yes | FAT |
If you want to write/burn an image to media you can use one of the following tools:
| Linux | Windows | BSD | Mac OS X | Notes | |
|---|---|---|---|---|---|
| Rawwrite | No | Yes | No | No | Floppy images only |
| dd | Yes | Yes (Using Cygwin) | Yes | Yes |
Floppy disk images
You can use 'dd' to create a blank floppy image.
dd if=/dev/zero of=floppy.flp bs=512 count=2888
CD images
As of version 0.95, GNU GRUB comes with support for no-emulation El Torito CD boot. Creating a CD image is much easier than working with floppy images and trying to stuff GRUB in them (and you get 650 meg more space too). Putting GRUB on a CD is now a simple matter of making a skeleton directory tree for the CD filesystem layout, copying the "stage2_eltorito" file in there, and running mkisofs with a specialized command line. See the GRUB 0.95 info node Installation > Making a GRUB bootable CD-ROM for details. Much more humane than those floppy games.
Handling of Partition Tables in images.
At the time of writing, only Apple's hdiutil can handle the mounting of partitions inside of an image cleanly. Linux requires some hacks to skip over the MBR sector and so-on.
Images with preinstalled GRUB
If you are looking for a ready-made floppy image with GRUB already installed, such has been set up by MartinBaute, and is available from the following mirrors:
- Clicker project at http://prdownloads.sourceforge.net/clicker/grub_disk.zip?download
- LibOSDK project at http://download.berlios.de/libosdk/fd.img.bz2
The image has GRUB stage1 / stage2 and an empty config file set up, so all you have to do is adding your binaries and editing the config file (see the GRUB manual for details).
Links
- Related thread in the forum: Topic:10549 You gonna find a nifty trick Brendan uses to build his own iso images - with NASM. (download missing)