Another Linux distro for car PC?

**COST Linux** · 04-22-2005, 10:54 AM

I don't like to bring this up again, but nothing out there seems appropriate.

I've developed my own tiny distro. I call it Cheap-Off the-Shelf-Tiny (COST) Linux. It is what it is - off the shelf software (RH based), and hardware (x86). Based on kernel 2.4, my distro has a 2MB base, runs in memory, crash proof. You can add on your own application from (or compiled) your own distro and add onto COST. If it's small enough, you can have it stored in RAM, or if it's too large, you can mount it read only. The system's configurations or other persistent information is written in a small (512K) read/write file system. Run time writes are written to tmpfs mounted on /var.

I've made my own routers/fw/VPN, etc. out of it. Like an embedded system, you can power it off without fear of corrupting disk. I wanted to use it in a carputer, but could not find a satisfactory windows environment for it. X is large enough. Plus KDE and GNOME is out of the question. I explored QT, QPE. I like the idea of a PDA-like interface for a car PC. I don't endorse the idea of having a keyboard/mouse control in the car like some other people do, and I don't believe you need all the apps that come with an OS - just a few specific apps, touchscreen driven. Your number one task in a car is to drive.

I tried QPE, but in order to run existing linux apps, you must port them to QT. Ideally, it must run X or tinyX, with a small window manager. I just stumbled upon GPE and matchbox the other day, and they re-invigorate my interest in carputer project again.

GPE is a PDA distro. It seems to require a lot of work to disassemble it and incoporate it into COST. Matchbox seems promising - it's a window manager that GPE uses i.e. PDA-like interface. You can run an x app on it with little or no porting, and it's also theme-able.

I think I can make a COST distro for carputer in a 64MB CF and 128MB of memory. I have a 3.5" SBC with VIA 667 Mhz CPU, it's smalled than a 7" widescreen LCD, so it can be built into a 2-DIN dash. I hope to have FM radio (USB), CD/DVD (slot load). I envision MP3 songs to be loaded externally via USB interface - whether it's a USB pen drive or USB powered HDD. An auto mounter must detect the presence of the external drive and mount it read-only.

Thoughts/questions?

**Nic** · 04-23-2005, 12:54 PM

ive been looking at pretty much the same stuff recently, fairly new to linux and ive only properly switched from windows a couple of weeks ago. My ideal would be having a m12000 booting from a CF card with all my media on a 3.5" USB hdd, easy to carry around uni and easy to update with new music. The other thing that i was really interested in was a phone interface, just sending/recieving messages and a decent incoming call alert/handsfree, widcomm on windows really sucks and if done properly i think incorporating a car handsfree into a linux machine would be really cool.

**TheLlama** · 04-24-2005, 12:02 PM

Wow, that GPE stuff is pretty darn coolo

**rubicon** · 04-24-2005, 03:48 PM

While QPE/GPE/etc. have their place, unless you're running the OS on the barest of platforms, I think you're cutting yourself short.

I run OZ 3.5.3 w/GPE on my Zaurus 5500 - it rocks. But unless I were running my Zaurus as my car PC, I wouldn't something like what you're describing.

A distro like Gentoo, for example, optimized for a specific machine - with only the packages you need compiled in, and tweaked as necessary - is currently optimum, IMHO. Quite speedy on an Epia M10k w/the latest 2.6 kernel (+ bleeding-edge patches); SWSUSP2 gets my resume times to a matter of seconds after POST, and when all is said and done I've got a full Linux install on regular hardware to play with if I decide to add/change/upgrade anything.

Best of luck with this, but I'm not entirely sure that folks who've committed to Linux on their carPC won't go a route similar to what I've suggested.

**egeekial** · 05-16-2005, 01:59 AM

Since you're considering GPE, you might want to look into Opie, too... I run it on my iPaq. But, I would have to say, Matchbox would be the best bet for running on x86. What would the footprint of Matchbox + tinyX be?

**COST Linux** · 05-16-2005, 09:32 AM

I'm currently trying to squeeze matchbox/tinyX into a 32MB CF, 128MB memory. Still have a lot to trim. Matchbox is not large, X is. The largest thing is the fonts, but most of them are not in use. The worst case might be 64MB CF with applications.

I don't think Gentoo or any full desktop Linux distro is a good idea. I'm trying to build an embedded PC, not a desktop. For a harsh environment such as in a car, you must eliminate as many moving parts as possible. I'm planning to run with no fan, no spinning disk drive, just flash. You can fit an out-of -the-box desktop distro, but it will destroy the flash drive quick because there is limited writes to the flash. My distro will run in memory, so strategic file system planning is essential.

**sumit_b** · 05-17-2005, 10:01 AM

Is the root filesystem mounted as read-only? I have done something similar, the only difference is that I gave up on X-windows. I write directly to the framebuffer device.

**COST Linux** · 05-17-2005, 10:14 AM

The root file system is rw so processes can create /tmp files if needed, but it's a RAM FS to avoid writing to flash. The /var file system is of tmpfs. The idea is if it's read/write, it should be RAM FS.

I want to be able to use existing desktop apps that are written for X. I've compiled X and the executable is 1.8M, Xvesa is 800K. With 32MB CF and 128MB memory, I can accommodate these. The largest thing about X is the fonts, which is 12MB. However, I don't think not all the fonts are in use. Eliminating them is a trial-and-error task.

**sumit_b** · 05-17-2005, 11:54 AM

Can I get my hands on your compiled X? I'd like to try it out on my distro. The hardware is 233MHz Geode SBC (same size as yours). Hope you compile for i586 or lower!

**COST Linux** · 05-23-2005, 11:39 PM

I've compiled it on my RH FC3, Ezra C3 CPU which has a CMOV issue. Good chance it won't run on your system. However, all you need is a host.def and the latest XFree86 code. I can send you my host.def file if you're interested.