So let's have a quick tour of what's inside the beast
First, as you may note, there are two models...TGS100 is designed for "PAL market", mainly for Europe. TGS110 is the same but for "NTSC market", mainly for US...it's the only difference between them.
TGS1x0 is based on IBM STB02500 chip. This is a PPC405 core running at 250 Mhz with additionnal features embbeded : audio DAC, video DAC, IDE bus, etc...everything is inside the chip.
It use 2*64 MB of DRAM memory. This memory is divided into 2 parts.
The first one is used by the chip itself for decoding purpose : MPeg buffers, demux config, audio decoding and so on...The second part is reserved for software.
This software layer is mainly built uppon U-Boot, for startup sequence, chained with Linux 2.6.9 kernel. Both of them consume 5 MB (soft, buffers for disk, network and so on...), so there are finally 27 MB reserved for "user space", as you can see on the kernel command line in U-Boot.
The whole software is based on TUXBOX Open Source projet, that is also used by other receivers like Dreambox. Remember this is primarily a DBOX2 project
As it's GPL project, source are published on
www.itgateusers.com, as mentionned on another post here. You may build your own firmware only with the provided CDK and your own Linux onto your PC.
But let's continue with hardware...
Power Supply is appart from the main board and is designed to provide enough power for any harddisk you may add into the box.
As PSU and HDD produce a lot of heat, case is designed to allow efficient air cooling for main usage. When a record / playback starts, a little FAN is driven ON, that will help the "natural" air cooling.
Front panel is made of a 4 digits green display, and also provide 2 smartcards (software activation with emucam) and 1 common interface slot. There's also the 9 in 1 memory card reader.
Network chip is a Davicom 9000 Ethernet 10/100 Full Duplex chip. From my memory, some Relook STB use the same.
DVB Tuner is a Sharp one. Seems to work fine and provide good signal level.
Remote Control Unit was first somewhat basical. It was using the same chip as DM500, and so has large conflict problems with LCD or PLASMA Tv (LG, Philips...) It has now been replaced with a 5 in 1 RCU, with a large range of code for driving TV, DVD, VCR and so on. This replacement was assumed with no charge for end users... not usual, but a good thing !
Firmware is stored in a 16 MB flash memory. You can find the actual flash partition scheme on official support site (
www.itgateusers.com) in "developers corners".
The most significant things about it is :
=> 1.3 MB partition for Linux Kernel (200 Ko free)
=> 5.6 MB partition for root file system (squashfs compression scheme)
=> 9.3 MB partition for /var (user settings and additional feature storage), jffs2.
Boot logo is stored in a dedicated partition (using specific strucuture, 720*576 picture for PAL, raw bitmap format compressed with gzip). This partition is 192 KB wide.
U-Boot also have it's 192 KB partition. It include serial (rs232 upgrade) support, tftp support and also (last release) IDE support for memory card reader access. Thus, it is possible to configure U-Boot to boot kernel from flash BUT with a root file system directly on SD card, thus removing the flash limit and the "read only" constraint of squashfs !
Using this, you can have a "SD card capacity only" limited file system, with full read-write acces
This feature is really great for firmware coders, has they don't have to flash each time they want to test a new code. They only have to upload their binaries to the SD card via FTP. In case of trouble, they only have to change kernel command line to switch back to flash memory root file system, without having to flash another working firmware. Great !
good write up mate
Linear Mode
