NFS (Network File System)

NFS comes in handy when wanting to run a file system of a remote host, for example to have all T2 tar-balls centrally stored, or to save space during the build phase of T2 (the chroot environment can work from a mounted file system).

Mounting a NFS Export

Make sure to have NFS compiled into the kernel (see the section called “Linux Kernel”) in T2 Linux it is enabled by default.

Start up the portmapper and NFS on the server:

rc portmap start
rc knfsd start

Edit /etc/hosts.allow to allow for your client:

portmap: clienthost

Add an NFS export entry to /etc/exports, for example:

/mnt/data 192.168.2.4(ro,sync)
/mnt/data localhost(rw,sync)

Re-export:

exportfs -r

Mount the file system on the client (make sure portmap is running):

mkdir /mnt/remote
mount remotehost:/mnt/data /mnt/remote

Check the /var/log/messages file if you don't succeed.

Note: NFS is quite fuzzy about DNS lookups. It is less complicated to have static IP configuration for the beginning.

CD-Writing

CD burning works very reliable - but IDE writers might need some extra care to be usable.

Some years ago some people in the Linux community decided that the SCSI layer should be the uniform layer to directly access non-disk devices in Linux. So up-to Linux 2.6 you need an SCSI emulation driver in order to access the IDE writer. Since the last Linux 2.5 Linux kernels and an updated cdrecord it is possible to access IDE writers directly without any need of SCSI emulation in between.

Which Driver to Use?

Most T2 Linux targets include the 'ide-scsi' driver compiled into the 2.4 kernel and the native 'ide-cd' only compiled as module. So as default the ide-scsi driver will be used for CD drives. And you should not have any problem - and skip the next paragraphs ...

If you have a kernel with 'ide-cd' complied in - or if you only want to use the 'ide-scsi' module for the CD writer and the 'ide-cd' for the other normal CD drives for performance reasons you need to tell the kernel to reserve the one IDE device for the 'ide-scsi' module - otherwise it could not determine which one it should prefer and just use the first match: 'ide-cd'.

The reservation is done via the kernel parameter 'hdc=ide-scsi' - where 'hdc' is the old-style name of the device. The parser for this options is rather simple and DevFS names - or other user-space mapped names - are not supported at this early boot-up stage. To determine the old-style name the files in /proc/ide/ or /usr/doc/linux24/devices.txt might be a help.

How to Burn a Waw ISO 9660 Image?

The low-level tool to write ISO 9660 (CD) images is cdrecord. Normally you want to specify at least the device node, the speed, whether you want to blank a CD-RW and of course the file to be written:

cdrecord dev=/dev/scsi/host0/bus0/target0/lun0/generic \
speed=8 t2-6.0.0-x86_cd1.iso

where 'dev=' specifies the generic SCSI device to use, 'blank=fast' would specify to blank a CD-RW (where 'fast' only blanks as less as possible and e.g. 'all' would blank the whole disc), '-v' would increase the verbosity to report more information, 'speed=8' specifies the write speed to use and the last parameter must be the image file to be written onto the disc.