System Layout

From OESF

Revision as of 15:25, 11 August 2007

nike bambino il figlio del dottor jekyll sfondi di settimo cielo gratis rameuse ragaza d argento natalie wood wassef video crea la tua donna il cacciatore di taglie david bisbal buleria narciso yepes midi vampir foto rassegna gastronomica escort genova vanderford video rivenditori accessori nokia 6600 a y gas contatore web base verticale playstation 2 olimpus p10 ingrosso materiale elettrico u2 - the joshua tree monitor lcd tft 19 marketing farmaceutico le colline hanno gli occhi film dvd master blaster dial my number scuola pavia charlize theron offerta cd-r terzetti otello profazio gps precisione cantanti di cartoons wilma hard disk esterno uscita a v motore stab gay fetish cool g vga hub il diamante fatale gps antenna primera guerra mundial auto palermo www music farm it gestori telefonia mobile memoria sd gb anal cumshot norton antivirus 2003 osito dormilon suoneria comporre unisannio sintoamplificatore pioneer - vsx le date dei concerti di biagio antonacci mercedes c coup angela borrero complitation frisell dissipatori asus camicie coreana fotocamere digitali casio ex z55 affordable health insurance tastiera con mouse pad il navigatore gps mitac 269 fantastici4 cappottino per cane notai a portogruaro prenderlo t amo nino d angelo gli avventurieri ingdirect it pulizia roma kiev lesbiche in azione corrieri viterbo processori amd sempron agriturismo il casolare deborah unger ballo palestra lavoro vigevano straordinario elettorale quando passi da queste parti... calendario e immagini di rossella bresci joypad wireless xbox accessori console encoder av mp4 anello solitario vienna cose fare cnmca haiducu abbonamenti sct cuffia infrarossi luiz caldas billeder voyeur campania software decoder e encoder base il volo del calabrone esibi fiesta diesel wake up simone sanremo krka in vacanza con mia sorella www irradio hotels a cervinia louge nikon af-d 50 1 4 e scabroso le donne cerco lavoro come modella mature porcellone catalogo prezzi accesori xbox ferrari berlinetta mmc per nokia 6630 telefono lg 3 amplificatori audio video misanoadriatico konta rex ri 700 monitor lcd 19 multimediale software invio sms www nomisma it hotel naviglio milano negrita sex l angelo e il pastore processore intel p4 2 4 radeon x850 agp corrida forno elettrico ventilato delonghi la danza delle strege renault 4 frog kingston-upon-thames toner lexmark w812 irty sakura wars. vol. 04 sandali miss sixty didle ciccione pelose siti lesbo ultimo album il fascino bigliettino augurio compleanno ju,p macchine digitali canon ixus video con alessia marcuzzi guerlain meteorites dolce gabbana slip rachel bianca foto cartoni porno toyota rav4 sol sony dz100 amd xp 2500 barton stampa cd fregne transessuali luka dirisio la rossa maschera del terrore carro t34 twentieth century-fox matrix pro g35 ex z500 pc5400 memoria ram deborah secco nua bmw 528 hotel centro grotte lombra della vendetta immagini per compleanno video di signore hard fukuoka shopping padrona elena email it donnevecchie epiciclo tubo gas masterizzatori dvd interno per notebook enschede gps yakumo delta 300 outlookexpress sms la terza generazione films pornografici vanessa vanna asus a7v600 x great american desert www huevo cartoon com enclosure 5 25 jetdirect en3700 video sesso severina video italiane libere nanna gibson moda mare basilicata gps smartphone miss fbi - infiltrata speciale granny porn reggione campania karena eileen regina edwards keri russel sblocco rete nece 616 esami di fisica cd mp3 cde-9843r frank avalon wlej video incidente linate just for you de lionel richie ti sposerei perche ==Overview==

This document describes the filesystem and directory layout of the Sharp Zaurus 5500, to help everyone understand better what happens when new software is installed, creating user accounts, and so on. It's not really a HOWTO in the sense that it doesn't explain "how to" do anything beyond understand the location of files and directories, and how these correspond to the ROM and RAM on the Z, and why.

Robert P. J. Day <rpjday at mindspring.com>

The memory layout

The memory on the 5500 is divided into ROM: 16M RAM: 64M, further divided into:

memory

32M for processes/buffers/cache

storage: 32M for additional file/directory storage

You can see the current usage of RAM by clicking on "Applications/System Info".

In addition to the above, their might also have additional memory on either a CF card or SD card, whose size and usage would also be displayed by clicking the same icon.

Superficially, all of the above storage/memory corresponds to the following locations or mount points by default:

/ ROM

/home RAM

/mnt/cf CF card

/mnt/card SD card

and in a terminal shell it will correspond with either of:

1. mount
2. df

While this is a fair approximation of how memory and directories are associated, it's actually quite a bit more complicated.

The directory structure

Again, simplistically, think of the two major mounts points as:

/ ROM

/home RAM

Initially, this suggests that all of the system directories like /bin, /usr, /etc and so on are read-only, but clearly this is impossible since there would be no way to do basic administration like adding a new user, installing new software and so on.

In fact, modifying system files is supported by the fact that there are about a gazillion links from the alleged system directories and files into corresponding directories and files under /home, which makes them changeable. For example,

/etc -> /home/etc

/tmp -> /home/tmp

/var -> /home/system/var

which makes everything in /etc, /tmp and /var read-write. So far, so good.

In addition, command and software management is also supported by carefully chosen symbolic links. Consider, as an example, just the /usr/bin directory:

/usr/bin -> /home/root/usr/bin

This implies that new software being installed under /usr/bin is actually going into the writable RAM, which is a good thing. But it gets more interesting.

If the contents of /home/root/usr/bin are examined, most of the contents are symbolic links back to files in /usr/bin.rom. This means that both the standard, built-in ROM commands appear to be in /home/root/usr/bin, even though they're really back in the read-only directory /usr/bin.rom. And any new software will go in /home/root/usr/bin. The same situation holds for the other directories /usr/sbin, /usr/lib, /usr/local, /usr/share and /usr/etc, which means there is access the pre-loaded ROM files while still being able to add new files.

This same technique is used for additional installation directories:

/opt/!QtPalmtop -> /home/!QtPalmtop

/opt/Qtopia -> /home/!QtPalmtop

Given the above, it's easy to see that the main software install directories are going to be:

/usr/bin

/usr/local/bin

/opt/{!QtPalmtop,Qtopia}

all of which, due to symbolic links, actually reside under /home somewhere.

The initial system directories

One final point. The initial contents of a number of the critical directories can be found as hidden tar files in the ROM-based /root directory:

1. cd /root
2. ls -a

.dev_default.tar

.home_default.tar

.var_default.tar

These tarballs are the initial contents of /dev, /home, and /var (which is really a symlink to /home/system/var). Doing a hard reset reloads all of /dev, /home and /var from these tar files.

When building a custom ROM the initial contents of any of these directories can be changed, by (as root on your Linux box) untar the appropriate tarball, make the changes, then tar it back up. You have to do it as root so that root is the owner of the files in the tarball. (fakeroot should work here, if you're familiar with that.)