Help the n00b - Whats the diff between a ROM and a Kernel?

[MatiasDuarte]

Hi all, I just recently recieved a C700 as a gift. It came with a power supply and nothing else. I\'ve managed to switch the language to English, but it\'s a really old setup. The ROM says it\'s version 1.00 JP. The Kernel says it\'s 2.4.18-rmk7-pxa3-embedix.

I see a lot of talk about different ROMs and different Kernels, but being totally ignorant I\'m a touch lost. Is the ROM an installation which includes the Kernel? It seems I can patch the Kernel without installing a new ROM - is that right?

I\'m very interested in any sytem upgrades that would improve performance and allow me to use the pressure sensitivity feature in paint programs. What\'s the easiest way to get such a system upgrade? Is there a single ROM I can just flash and have it all get installed at once?

Which ROM should I choose for maximumn compatibility with exsisting apps?

Actually I\'m only interested in painting and multimedia playback on the Zaurus (I\'ll just use my Sidekick for text editing, email, web browsing etc.). I\'d love to just run a paint program and a MP3 and a video player on the Zaurus - which ROM would be best suited for that?

Any advice would be much appreciated!

[doc]

]]] I\'m a touch lost. Is the ROM an installation which includes the Kernel?

Yes.  The ROM is the entire working system.  The Linux kernel is the core of the operating system which acts as a mediator for your programs and hardware.   I haven\'t yet tried to upgrade just the Kernel of a ROM, so couldn\'t be much help there.

[Stubear]

Upgrading just a kernel is the same process as upgrading a ROM.

Note: a ROM does not always contain a kernel.
Usually the kernel is a seperate file (zImage or zImage.bin) downloaded with the Rom and updater script (Cacko is a good example of this) while tkcRom only had the rom.

To upgrade just the kernel put the updater.sh and the kernel file on your SD/CF card without the rom image and follow the normal procedure for lfashing - will be much faster as the kernel is usually only about 1Mb as apposed to 20Mb+ for a ROM.

Stu

[ScottYelich]

it\'s a bit misleading... sharp is destroying terminology.

ROM is usually \"Read Only Memory\" but in sharp terms, it basically means \"operating system\"
the \"operating system\" is stored on \"flash ram\" or \"flash rom\" or whatever... so, this is probably
where the ROM = OS comes from.

A kernel is what some people would call the operating system -- where as the \"ROM\" OS is stuff
like applications -- but we have microsh!t to thank for destroying the meaning of \"operating
system\" in the name of \"innovation\" and monopolistic practices.

Basically, you can think of it as just this... the \"ROM\" = the base installed application suite
and is not overly tied to the kernel.  The kernel is the primary application, or lowest level
of the operating system that allows other applications/programs such as device drivers
and word processors to run.

There are many docs about flashing on the Z -- the thing there is that when you \"flash,\"
you are going to be writing to the flash ram/rom area... but, you can write a kernel, OS
or both.  So, it shouldn\'t be thought of that flashing equals one or the other, as it can
be either or both.

Scott

[lardman]

Note that the kernel requires modules to operate and these modules are in the filesystem portion of the flash image. Therefore you can\'t just mix and match kernels and filesystem images.


Simon

[MatiasDuarte]

Thanks guys, that clarifies a lot!

Many of the online docs and posts talk about using a new \"ROM\" to update the OS. Therefore these ROMs could either be:
- replacements of the higher level OS modules (like the window manager) and what are usually seen on the PC as the installed applications (web browser, etc).
- the above plus kernel replacement which improves the very lowest level functionality of the system.

Is that about right?

[lardman]

ROM basically means a \'ROM image\'

Normally people talking about ROMs mean a kernel and a fileysystem image together.

If you replace the kernel you almost always need to replace the fileysystem image (because of the modules) unless the filesystem is writable and you can add the modules before you flash the new kernel (or if the kernel is basically the same one with extra options you may get away with it).

The filesystem image contains amongst other things:
kernel modules
basic libs and programs (like libc, sh/bash) which pretty much all Linux programs need (found in /bin, /lib & /sbin)
slightly less basic libs and programs - tar, less, ls, more (but still fairly essential, found in /usr/bin, usr/lib, usr/sbin)
GUI interface libs, programs and other odds and sods - Qtopia/Opie/X11 & Window manager/etc.
Other (non essential) applications (opera browser, hancom suite).

Hope fully that makes some sense.


Si

[mielikki]

My 5600 has (according to the manual) 512KB ROM, 64MB flash memory, 32 MB RAM.

What\'s in the 512KB ROM? Is that where the maintanence menu is? Is that really ROM or is it some sort of PROM? When we \"flash the ROM\" are we changing anything in that ROM or just in the flash memory?

The flash memory, from what I have read is broken into 2 partitions? One that is read-only for the kernel and \"built-in\" apps. (I guessing that is the stuff that gets replaced when we \"flash the ROM\".) That\'s the one lardman discussed above? The other is read-write and is where we as users install applications and save documents... (Although maybe that explanation is only true for the stock kernel?)

I\'m a n00b, too, so what I have said here is what I understand so far, but I may be way off base.