Newsgroups: comp.sys.transputer
From: luigi@labinfo.iet.unipi.it (Luigi Rizzo)
Subject: Re: Disk Interface?
Organization: Dip. di Ingegneria dell'Informazione, Univ. di Pisa
Date: 27 Jun 1994 21:21:25 GMT
Message-ID: <2unfsl$uhn@serra.unipi.it>

In article <772713591snz@dwyn.demon.co.uk>, gil@dwyn.demon.co.uk (gil copitch) writes:
|> In article <772448364snz@sunny.demon.co.uk>
|>            murray@sunny.demon.co.uk "murray elliot" writes:
|> 
|> > I would like to know if anyone has any experience in interfacing
|> > a hard disk (IDE/PCMCIA/whatever) to the transputer - are there
|> > any standard interface TRAMs available?

IDE disks are *extremely* easy to interface. They require a simple
parallel IO interface, with a few I/O ports and address lines.
A student here has just completed a very simple interface between
32-bit Transputer and an IDE disk using a PAL (22V10), and a few
other components: 2 74LS245, 1 74LS244, 1 74LS374, less than $10
worth of hardware.

Using a simple design, the disk data lines are connected to the
lower 16 bits of the Transputer data bus, and disk register are
mapped in the high memory space of the Transputer.  Speed is around
300KB/s when programmed in C. I think you can go much faster (the
Transputer is a 20 MHz part with 4 or 5 cycles DRAM access time),
by using the following techniques:

- use assembler language for the inner loop which read/write a sector
  from the disk;
- take advantage of the block move instructions, by either using a 16
  bit transputer, or using a more complex circuitry to use 32 bit data
  transfers.

The latter is what can give you the best increase in performance.

As for the DOS file system, once you have written the (simple)
read/write routines, I think you can compile the mtools sources,
which implement the DOS file system. We will try this after the summer.

Email me if you need more details.

	Luigi

====================================================================
Luigi Rizzo                     Dip. di Ingegneria dell'Informazione
email: luigi@iet.unipi.it       Universita' di Pisa
tel: +39-50-568533              via Diotisalvi 2, 56126 PISA (Italy)
fax: +39-50-568522
====================================================================

