Accessing HD in a satellite box through USB

Share a Hard disk....

I have an HD in my satellite box, and i want to access (from the PC) to the hd thru USB.
So i plan to use a n USB2IDE converter. on IDE cable connected on one side to the satellite box, on the other side to the USB board and in the middle, the hard drive.
Of course, i won't be able to access the HD simultaneously !!!
Does anybody here already do something similar ???
Thanks
Daffy :?:

Re: Share a Hard disk....

Hi,
I am afraid if you do what you explained here, you will kill your USB device or your satelite box or at the worse case, both.

What you are doing is to connect 2 masters into a slave. Unless you turn off your satelite box before connecting your USB device, and vise versa, you will be able to do so, othersie, if you keep both of them on at the same time, you may burn the driver section of the both units, depending how powerfull they are.

:idea: But thats an interesting idea, will be interesting to know if it works

/Farhad

Re: Share a Hard disk....

It's interesting. I wonder what OS your satellite using. They imght not use FAT or NTSF for the Hard drive, so you can share. If the harddrive you the same format, I think it's possible

Re: Share a Hard disk....

from what i understand.

you have a harddrive in your satalite box, on a ATA bus.
Which you want to access from your pc, through usb, by adding
a ata usb converter on the cabel inside the box right??

Yes This is more or less posible..
but you need to take a few steps.
You will need to find out if the ATA controller in your satalitebox will go into
"tristate" (not put 0 nor 1) on the ata bus when it is turned off!!
if it does not enter tristate you will have Some (random) signals on the bus from the controller when you use your usb adapter.
This ofcource is also the case with your ATA-usb controller..
and hence it will not work!

(may fry one of the controllers, as one may be trying to pull the bus to low, while the other wants to make it high. The Stronger one Wins!! (gray-ish smoke may apere around the loosing part!) )

So What i would personally do is make a "large" Swich to change the harddrive between the two buses. i am ofcource not talking about a big manual 40 Leded swich. but rather an array of bus multiplexors..

These multiplexors could then be activated by the 5v from the usb on your usb-ata controller.
This way. When you connect the usb plug to your satalite box The multiplexors will swich your harddrive from the satbox to your usb-ata controller.
and the drive should pop up in your computer.

What will hapen to the software on your sat box when you swich it back again i cannot say. but most likly a reboot is nessesary!
(this could be automated when you remove the 5v usb again!)

I used a simular method to Add usb connectivity to my m3po (mp3 player)
plans may end up on the internet when i get around to it. but curently my plans is on the other side of the atlantic!

nb. you may be able to put the usb-ata and satbox ata controllers into tristate whith their chipselect or simular. this way you can just add a second controller to the bus. and swich between them.
if you plan to use the cdromdrive that may reside in your satbox??
you should check out the ata-usb controller from texas instruments which can handle both master and slave!!


Hope my post helps / inspires you And indeed happy hacking!"

/kyndal

Re: Share a Hard disk....

Hi Kyndal, where have you bought the kit to add usb port to m3po?
Gianluca

Re: Share a Hard disk....

it is not something i have or have made, it is only a posible way to do it.
the usb-ata controler can be bought on ebay for 15$ or so.
the multiplexor aray is the part you need to design.

it would in theory work as a row of relays 30 or so (signal lines only)
that would swich the harddrive between the SAT-box ATA controller,
and the USB-ATA controller..

so when the usb is attached "The relays" swich the harddrive connections
to the usb controller..
and the computer is able to use the disk.. Sat box wil most likely crash due
to loss of the disk?

these relays are ofcourse "multiplexor chips" or other Programable logic??

/Kyndal

Share a Hard disk....

you cannot use leave the the sat-box on while using the sata.

if the sat-box was writing or reading from the HD and u suddenly change the "relays" , not only the hard disk and the sat can be dammaged but also your pc IDE or MB.
the safest thing is to modify a little your sat-box and make the HD extractible. (Always Shutdown the current device before using it).

Regards
Cortex

Re: Share a Hard disk....

i agree. there is no way to know how the sat box will react
if the harddrive is suddenly "unplugged"
i dont believe it wil damage any components, except maby the filesystem. but who knows?

yes the best bet is to power off, the sat-box and power the harddrive
and usb attach it..

Weather the multiplexing circuit is neccecary, will depend on weather the motherboard. sets tristate on the IDE bus while turned off???

/Kyndal

Share a Hard disk....

we forget about the speed of the data
the 3 states must be accept the speed used by IDE

Re: Share a Hard disk....

speed??

im not talking about speed. im talking about tristate..

a controller can set the I/O pins to 1 or 0 but when off
some controllers can set the I/O in "tristate" meaning it is not 1 or 0

meaning that something else can use the same "cable" without worries
about the other controller, trying to keep 1 or 0 on that line..

/Kyndal

Share a Hard disk....

i understrand your point

but the Frequency that enter in the Tristate must be low(depend on chip check datasheet).
else the chip follow the input in his output.