Re: [microblaze-uclinux] Implementing FAT on uCLinux

[Alejandro Lucero <alucero@xxxxxxxxx>]

Hi Farhan, 

You already have FAT filesystem available with Linux/uClinux.

You talked about RTOS on microblaze, but latter just mentioned SATA and file 
system issues. I will release the next week (perhaps two weeks) a porting of 
RTLinux (free version) to uClinux on microblaze. 

Look RTLinux reference at:

http://www.linuxdevices.com/articles/AT3694406595.html

RTLinux tasks can not access hard disks directly. Instead, they send data to 
Linux processes through RT fifos and then these normal user processes write 
data to disk just like another one. You can use for that the filesystems 
supported in your kernel. Although this works fine, the indirect path has a 
cost in performance and in resources, since you need a buffer large enough to 
take into account Linux performance. Moreover, in this case you have Linux 
tasks and RT tasks using the disk, but without any guarantee RT tasks disk 
requests will be done before Linux ones.

I worked in a project to enable that RT tasks can access hard disk directly, 
using a specific file system very simple and written from scratch. You can 
use the same disk for LInux and RTLinux and the implementation guarantees 
that RT tasks will be done before any Linux one. This is far away to pure 
determinism accessing hard disks, but it is a first step. 

Look at www.lutherfs.com

I hope that information can help you.

Regards.   

On Friday 05 January 2007 12:10, Sheikh M.Farhan wrote:
> Hi there,
>
> My name is Farhan. I am exploring porting an RTOS on microblaze. Let me
> give you details on the challenge I am facing. I have an FPGA board with
> Spartan3. There is a SATA controller from Silicon Image (Sil3512) on the
> same board connected to the FPGA. A SATA hard disk is connected to the SATA
> Controller. This is actually an embedded system for real time data
> acquisition with A/D on board as well. I need to implement a simple FAT
> (file management system) on the FPGA so that I can read and write from/to
> hard disk. Implementing Fat12/FAT16/FAT32 in Verilog/VHDL is not a good
> idea. However, implementing the same in C makes more sense. Can anyone
> guide me how ucLinux can help me in implementing this? Has anyone done such
> a thing before? Any directions...........?
>
>
>
> Best Regards
>
> Farhan
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