[LUAU] Intro

[MonMotha]

Jim Thompson wrote:
> 
> On Aug 10, 2004, at 10:37 PM, MonMotha wrote:
> 
>> Jim Thompson wrote:
>>
>>> the non-MMU parts that made uClinux special are now part of the 2.6 
>>> kernel tree.
>>
>>
>> Yes they are, though I haven't had a need to play with it yet as I do 
>> mostly ARM and embedded x86 work (well, and work on things that will 
>> NEVER run Linux)
> 
> 
> never say never.   :-)

OK, port Linux to an 8051 with 256 BYTES of RAM and (at most) 64k of ROM.  :-)

> 
> Most of my recent work has been Xscale (which is arm at its core) and 
> VIA's embedded x86 parts, though MIPS still
> features as a strong #3.
> 

I've been doing some MIPS work recently (reverse engineering the DDR machine). 
I like the instruction set, but the arch has some "quirks" that can really "irk" 
me.  Haven't run Linux on anything MIPS yet though.

...
>>
>> Well, while we're on the topic, I have some of my "hack it out until 
>> it works" based things, though recently I've been experimenting with 
>> buildroots and maybe OpenEmbedded.
>>
>> http://monmotha.mplug.org/flplinux/
>> http://monmotha.mplug.org/smallsys/
> 
> 
> Buildroot was the basis for the very early musenki tree 
> (http://www.netgate.com/~jim/Musenki), which begat the Vivato tree, 
> which ...
> 
>> http://monmotha.mplug.org/tuxscreen-image.jffs2 is what runs on my 
>> tuxscreen, though I need to redo it.
> 
> 
> The musenki boards ran jffs2 as well.   The image included things like 
> an SSL-enabled web server and open ssh (this was in the days before 
> dropbear and friends).

JFFS2 is pretty much the de-facto standard for linux filesystems on raw flash 
(it gets used on linear flash PCMCIA cards too).  Transparent compression, wear 
patterning, etc.  Very nice filesystem.

Yeah, all those older images that include SSH support (I don't know if any 
actually do, though I made some that did) all used OpenSSH and therefore had to 
include OpenSSL.  Cost you a LOT of space...

> 
>> All those are very old, but demonstrate what kind of space you can 
>> actually cram Linux into if you work at it.
> 
> 
> similar dates even.  Hmm!
> 
>>  I've seen Linux fit in under 1MB before.  You can have an entire 
>> userspace in under 500k if you really want to (busybox/uClibc and some 
>> shell scripts, statically link busybox to uClibc), though it won't do 
>> much other than boot.
> 
> 
> We sell linux-based 802.11 devices that fit everything (web server, ssh 
> and all) in under 2MB.

I have a similar image I've been working on.  Do you know of an SSL capable 
webserver that doesn't need OpenSSL?  Apache/mod_ssl is just overkill for a web 
frontend!

> 
> 4MB allows me to add things like snmp, captive portals and ad-hoc 
> routing (olsr).

Yup :)

> 
> 8MB of flash is pure luxury.
> 

We're currently using Compact Flash cards in ATA adapters, rather than real 
flash, so space isn't much of an issue (do they even SELL 8MB flash cards 
anymore?).  One of my "embedded" systems was actually a Dell PC with a CF<->IDE 
adapter in it! (Heck, it even had a hard drive for logging, but I went to great 
lengths to make sure the system would keep running even if the hard drive 
completely failed; it would even boot up with a bad HDD!)

> And then I have this 7 Ethernet, 2 miniPCI ixp425 board with 16MB of 
> flash/64MB of ram here.   No idea what I'm gonna do with it yet.   :-)
> 

Well, I've got 3 webpals sitting around (1MB flash, up to 16MB of RAM, or 64 if 
you're willing to do a hardware mod), and a General Instruments/Motorola 
DCT-5000 MIPS based set-top box (that is MINE thank you, not the cable 
company's) that I need to find something to do with.  The DCT-5000 has a LOT of 
stuff in it (much of which nobody will ever be able to get specs on, at least 
not before it snows in hell due to the heat death of the universe occuring).

My x86 development has mostly been on dual ethernet AMD Elan systems with (up 
to) 64MB (yes, 64MB) of RAM, a CF slot, and a PC/104 bus (that I need to make a 
daughterboard up for).  Mostly acting as routers (which 64MB lets you do some 
very cool stateful filtering stuff), but also just in some other weird applications.

--MonMotha