Re: TI-H: special component
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Re: TI-H: special component
That was kind of the idea. :> I'd buy a 386, cept that i want something
nice and small...and unfortunately 386 MB's aren't small. Besides, i think
it would be fun to build my own NIC out of a microcontroller. Course,
prolly need some onboard SRAM for cacheing...but anyway :>
-- Jon Olson
At 10:09 AM 6/19/98 -0400, you wrote:
>
>Save yourself a huge amount of trouble, buy a 386 DX/8MB at a computer
>or ham show, and get a cheap 10mbit nic. You can probably get everything
>you need for under $80. Go home, install linux, and you're set. I think
>doing this kind of thing from the ground up yourself would be like
>trying
>to redo 10 years of PC hardware and software development!
>
>Bryan
>
>Jon Olson wrote:
>>
>> Don't you think that the chip would however, get backlogged with data after
>> a while? i mean...it could in theory bring in the data and send it back out
>> that quickly, however if it's planning on doing anything real with the
>> data, i don't think that this will work at all well. however, if you can
>> find a way to make it work on a 10 Mhz network. Please tell me. I've been
>> considdering building a little device that connects to a modem and to my
>> dad's office network and allows me to dial in and execute various tasks
>> (i.e. reboot my servers there, connect via telnet to some of the firewalled
>> workstations, that kind of thing).
>>
>> At 08:33 AM 6/18/98 -0700, you wrote:
>> >
>> >On Thu, 18 Jun 1998, Jon Olson wrote:
>> >
>> >> Seeing as the PIC only operates at 10 Mhz and the network operates at
100
>> >
>> >Just a minor technicality, but I think the high-end PICs max at 20MHz..
>> >
>> >They take 4 clock cycles to make an instruction cycle, so it's getting 5
>> >MIPS. A 10 Mb/s (megabit) network (in theory) pushes 1.25 MB/s (megabyte)
>> >of data. So if you had some sort of a shift register taking the data from
>> >the network line and presenting it a byte at a time, then I think a 20
>> >MHz PIC would be able to switch 10 Mb/s network traffic. (Did I calculate
>> >all that correctly?) A 100 Mb/s network (also in theory) moves 12.5 MB/s
>> >down the line. Since a PIC can read its I/O ports in a single instruction
>> >cycle, it can take in 5 MB/s at 5 MIPS. So it has enough room left over to
>> >push 10 Mb/s traffic back out another port, but it doesn't have enough
>> >power to even read in a 100 Mb/s source without losing frames.
>> >
>> >So anyway, like Jon said, 100 Mb/s traffic is definitely out. But I think
>> >10 Mb/s might be possible... unless I don't have a clue what I'm doing,
>> >and that is also possible.
>> >
>> >--
>> >Greg Hill
>> >greg-hill@bigfoot.com
>> >www.comports.com/link
>> >
>> >
>
>--
>Bryan Rittmeyer
>mailto:bryanr@flash.net
>http://www.bridges.edu/horizon/
>
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