Atari ST computers and mass storage

 On this page I will present different hardware and software solutions for still actual mass storage for Atari ST(E) computers. In first place hard disk interfaces, drivers for them. And some simple programs for support - speed measurement etc. Modification of Mega STE's ACSI/SCSI adapter to allow access over 1GB.

First, little overview of  compability with PC DOS hard disks - it is very important because of easy file transfer.

Available solutions:
 First was Atari Megafile - complete adapter + MFM/RLL hard disk with case and power supply. Now it has mostly historical meaning. Slow, low capacity.
 ICD made some nice ACSI-SCSI adapters, which overrided 1GB ACSI limit and worked very fast.  AsSCSI ST, Link adapters ...
 Mega STE internal ACSI-SCSI adapter: limited to 1GB, but reliable and with good speed.
 Internal IDE adapter: first in ST Book and Falcon. Possible to add for all ST(E) machines. Needs byte-swap if use DOS compatible medias.
 Internal SCSI port:  TT and Falcon.
Above are most popular solutions in era when Atari corp. still made ST and followers.

Today (21-st Century) solutions :
  Flash memory cards instead classic hard disk:  so may using Compact Flash cards instead IDE hard disks. Possible problems with some cards due to bad IDE/ATA timing.
  SD cards on ACSI port: Satandisk (slow) and UltraSatan - faster, supports hot-swap, 2 cards at once.
  IDE on cartridge port: Paskud - discontinued years ago. Read speed was good, but write not.
  Internal IDE board for STE - by placing in CPU socket or Blitter socket no need to solder a lot. Discontinued.

The 'train' solutions: ACSI-SCSI adapter + SCSI-IDE adapter . Not cheap. takes place on desk, but may be good for people who already have some good ACSI-SCSI adapter. There are some SCSI-SD adapters too, or IDE-SD ... Possible problems with configuring, reliable work,
If want to use with CF cards need IDE-CF adapter which has connected DMA lines ! I say it because I have one which has not (and works well with USB card readers or Atari IDE IDs).

Above list is of course not complete. But most popular choices are present.
The future: there is still space for improvements. ACSI port is faster than Atari DOCs say. Cartridge port can be used in very fast way. Even SCSI adapters can be faster. So, soon will be available some new adapters.

IDE interface
Internal IDE interface for ST and STE machines. It is designed in 1992, and still is actual - good for Compact Flash cards too. Speed is better than by ACSI interfaced drives, especially by machines with blitter (up to 1800KB/sec). Project is for people with some soldering and electronical knowledge. Unfortunatelly Atari ST machines have no internal bus connectors (except Mega ST serie), and soldering is only way to make some specific hardware extensions. Interface will allow to connect IDE hard disks, CD ROM drives and other Atapi compatible devices to an Atari ST(E) computer. It is AHDI compatible, and all standard drivers should work on with it. Additional it supports optional ROM upgrade to TOS 2.06 .
Full package with PCBs - double and single sided, GAL files
Flashable TOS x 4 - for 4 TOS versions, full DOCs

Pictures of cabling example in STE
Because of easy data transfer, usage of PC (DOS) compatible partitioning on disks is recommended. But in such case byte-swapping is necessary, what decreases transfer speed of disks.
There is a simple solution for having both: speed and compability: hardware byte-swap. Without additional components, just by twisting cable - twist lines 3-18 similar as by floppy cable by PC,  or solder it so, that D0-D7 is swapped with D8-D15.  twist1.jpg

 Special driver is required for this, twisted solution. Plus, some little modification of TOS 2.06 ROM, to may having autoboot.  Now, there is a better TOS 2.06 mod./patch for twisted IDE - works with regular and twisted cable, much faster boot. See at page bottom.

 Schematic of old PC ATA IF -
it is from PC HW book from 1992. And it inspired me to make IDE IF for Atari ST.

Diverse driver versions for above interface  In archive is driver V0.7  - runnable from floppy, and autoboot installer V0.91  (works only on TOS 2.06 and patched TOSes (done for 1.04, 1.06/1.62, KAOS 1.4.2) - see at page bottom).  Autoboot is for normal and twisted (dual driver). Required BigDOS is included. Works with Falcon too.

   Speed with twisted cable on Mega ST (using blitter) and CF card :

Driver specs:   
 Video   of installing and running on KAOS TOS - 2 MB, Xvid . It's with added boot code for regular and twisted IDE in TOS ROM.

Multiple partitions on memory cards under Win XP

 ACSI/SCSI attached disks
Driver for disks attached on ACSI port, or ACSI-SCSI adapter: it can work with Satandisk for instance. With SCSI drives attached via Mega STE's internal adapter.
Driver specs:

 New versions of drivers, together with partitioner are under work for longer time, and will be soon available. It will be commercial, for low price of 10 Euros.
  The features:

Modification of Mega STE's internal ACSI-SCSI adapter

  Such adapter is limited to access only 1GB on drives, what is little today.  Fortunatelly, modification is possible with practically zero material cost.
Description of modification
mintf32.png  Accessing 11GB FAT32 partition under Mint with modified adapter and SCSI drive.
Special driver for this mod. specs. are generally same as for above driver, with important difference, of course: max accessible disk is 2000 GB. No other driver which can using benefits of this mod. - it means that you may using other drivers, but with 1GB limit, of course.

Speed  - transfer and access speed measuring with some interesting results and programs for measuring

Booting from IDE hard disk/CF card by TOS 1.04, KAOS 1.4.2 and 1.62(1.06) : It is ROM TOS patch, so you need to programm EPROMs with new content. Adds autoboot from IDE drives, Unfortunatelly, it will not work with AHDI or Hddriver. Reason is that their loaders use new XBIOS function #42 for sector read from IDE drives, which is present only in TOS 2.06 or 4.xx . If driver has own IDE sector reading code for load second stage then it will autoboot - drivers on this site are of course such.
New patches made in Nov. 2008 :  dual boot - from regular and twisted cable IDE, fast boot, only 1 driver installation for both types. For TOS 2.06, 1.04, KAOS 1.4.2 , TOS 1.62/1.06  .
The code:  SRC for TOS 1.04   all patches with instructions in 1 archive

Important:  There is corrupted version of UK TOS 1.62 available at many places. Recognisable by 2 bad values: address $15762 has value $10, instead correct value 0 . Address $269A2 has value $3E instead good $2E . Recognisable by too wide desktop window in low res.  too .

If adding this patch is problem, send me a mail and I will send ROM image file(s) .

P. Putnik   Okt. 2007,  April, Nov.  2008 .

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