Mass storage (hard disk, now rather SD card) with Atari ST family

[Petari]

 I saw really lot of pages, threads about it, and can say only that most of it is far from good and useful. Errors, shallowness and often in some commercial purpose.
 Now we have diverse SD card adapters, and probably most sold is ACSI2STM - in diverse variants. It changed since first releases, and now pushes so called GEMdrive mode .
 
 Let see what is on Github about : How hard disks work on the Atari ST
Quote: "Remember that using ACSI drivers is discouraged, you should probably use GemDrive unless you have very specific needs or want an authentic user experience (read: having a hard time struggling against old buggy software)."
 This is so idiotic, likely just in interest to force using GemDrive (so buy ACSI2STM and not some other adapter) .  Old SW is not buggy at all. Sure, there are some bugs in some, but generally most of it is pretty decent and well tested.  Unless thinking that it is bug that old SW does not support some new hard disk filesystems and like :-)  Sure, it should support LFN, FAT32, 2 GB partitions (in era when usual hard disk sizes were about 100 MB) ...
Then there writes that it (ACSI port) has no real name  - hahaha .
"Mega STE internal hard drive
Some models have internal hard drives, however it seems that only the Mega STE has an internal ACSI drive, sharing the DMA port. By default it is set on the device id 0, but this can be changed by internal DIP switches."
Stacy has it too. And it is not ACSI drive, it is SCSI drive + ACSI-SCSI adapter.  Why people with so low Atari ST experience writes about this things at all ? Complete bad approach - but hey, they are sooo smart, so know it better than those who used such machines 

AHDI driver is not full of bugs. And limitations are actually in TOS self. You can read about it on my site: Atari ST family and mass storage

TOS limitations can be overridden in different ways. Surely most useful and easy to implement is TOS/DOS compatible partitioning and hard disk driver. It does not need any HW changes, just SW - partitioner and hard disk driver - easy to install. And can do it even without floppy or Gotek.

 The real question here is : with what SW most of nowadays Atari ST family users use them ? I'm pretty sure that it is gaming - playing good old games in first place. As lot of people plays even older, 8-bit games.
 Now even can buy new version of Atari 2600 (with cartridge port for games on ROM cartridges) .
Sure, there is lot of quality productivity SW, but using them now, when we have several thousands time faster computers and much more advanced SW ?  Now simple Internet browsing needs min 2-4 GB RAM .

 So, my activity is about making good old games working from modern storage - what is now really cheap considering capacity.  But making SW written for floppy run, with copy protections in looot of ways to work from mass storage (now SD cards, CF cards) is pretty hard. Even if game has hard disk install option (program what does it) it may not work good - some have install only to subdir in root of C: - not good for thousands of games on mass storage. So, it needs corrections too.  Plus, and I saw many such cases - there is low level hard disk access in code - what means not access to some files, DIRs, by it's name, but to physical sectors . And that's what will fails with GemDrive . I wrote about it to man behind GemDrive, and just got reply in insulting style - he is smart, I'm nobody. Sure, after doing over 2500 games I know nothing !  This is real problem in 'Atari community' - some just push own ideas, limited knowledge, and do not listen to other's experience, knowledge (not so limited).

 All in all, please do not believe everything what can see online. I did not say anything new, of course.
For running good old SW, games we don't need new TOS (like EmuTOS), new hard disk systems. Best way is compatible TOS version - so regular TOS 1.00 - 4.04  or my improved TOS versions, which are made to be compatible as much is possible with original TOS versions. And of course hard disk driver what is good with old SW and TOS/DOS compatible partitions. Latest mean easy data transfers with modern computers - Windows, Linux, MacOS . And lot of things can be done on them way faster than with old Ataris .
 

[Petari]

And what can see on ACSI2STM doc

Well, they even don't know that Falcon has no ACSI port.
Works with all SD cards except SDUC (was not tested yet). Well, my experience is that very high speed newer SD cards may have problems, especially by writing on them.

"In GemDrive mode, the SD card must be formatted either in FAT16, FAT32 or ExFAT format, with a single partition (the standard format for SD cards). The partition size is limited to 2TB."
So, only 1 partition. How it will look with some 10000 DIRs ? And surely will work slower than smaller size partitions. Yes, it is basically same is in Steem and Hatari - where 1 DIR on host is assigned as Atari drive.
 TOS supports up to 14 partitions C-P . And more partitions means not lower speed, actually contrary - less data on 1 partition means faster work.
 They say that few games with no copy protection will work. Yeah, considering originals. What about hard disk adaptations, patches ? As usual they have no clue what all is made.

"Software relying on bugs
These programs use the normal GEMDOS interface to access disk drives but rely on weird patterns or buggy TOS error codes to work properly."
 And same idiocy as on page about how hard disks work on Atari (first post in this thread).
Buggy TOS error codes - huh !  They are not buggy. May be different than some later widely used ones - it is really so stoooopid to expect from SW done 40 years ago to be by some later standards .

"Software doing BIOS access

These programs access low level disks using BIOS or XBIOS interfaces.

Programs usually working like this:

    Most disk utilities
    Maybe some very weirdly programmed games
"
It is not weird to use (X)BIOS call to determine is it running from floppy or hard disk. I saw it many times, and is usually by games with hard disk install option, or declared that work from hard disk.

 And they mentioning my early, freeware ACSI driver from 2008.  I did lot of it from then.
What about extra functions like Virtual Floppy, automatic Desktop drive icons creation ? By them, it is also bug of TOS that only icon for C is created ...  Is it bug that TOS is in limited size ROM ?
 Lot of it is done with compromises because HW prices were pretty much higher then.
And really, why such huge disrespect toward Atari ST designers, OS programmers ? Sure, there were some smaller errors, maybe few bugs which show in rare cases.  Just one example:  it crashes when in drive Window in Desktop some file is of size 10 MB or more (TOS 1.xx) . Well, I did not know about it when I used my Atari at 1992 with 40-160 MB hard disks, simply because were no so large files.  I saw it first time somewhere at 2008, when used Steem with it's hard disk system . And. btw I fixed problem in my iTOS .

[Petari]

 I need to add here some things. Used some harsh words - idiotic, stoopid and like. Well, how should react on writings which say that TOS, old Atari SW is buggy.
" rely on weird patterns or buggy TOS error codes to work properly"
Really, this is something stupidest I did read in some computer related text, article.
TOS was released in 1985 and Atari ST had good sales, lot of SW from diverse firms, hobby programmers and like was released. And of course TOS DOCs by Atari, lot of it in magazines, books.  I bought in 1987 April Atari 520 ST, and in same time Atari ST ProfiBuch - some 700 pages, and there were detailed descriptions how to use TOS function calls (Trap #1, #13, #14 ...) . All it was pretty consistent, and nothing weird. And of course it stays for error codes - and was not so much of them.
 In same year, 1987 first updated TOS v. arrived - v 1.02 . It was not bug fixing, but doing diverse things better. And updating OS was normal thing by other firms too. I barely used 1.02 - went on 1.04 and 2.06 few years later. And they have significantly better hard disk support, filesystem.
 I'm not saying that TOS was perfect - there are some flaws, and I wrote about some on my Atari WEB pages.
Some fixes appeared too - like Folder 100 - what is not bugfix. It just expands something - of course at price of some RAM used. I never needed it. Well, I programmed in ASM since 1987, made some floppy util SW, RAMdisk ...   In 1992 went on IDE hard disk with Atari . And that was when did making floppy based games to work from hard disk. It was especially useful with 4 floppy based Microprose F1 GP .

 And more about it:  some call it 'patching', some 'conversion', some 'cracking' . Surely deactivating copy protection is needed, but that's only part of needed things. Conversion is not really good - there is need first to understand game's code - like custom floppy code, and I saw really a lot of diverse solutions, some with really weird and hard to follow, trace, understand code. 
 I say that 'adapting' is best term. Can not convert custom floppy code, you need to adapt it to hard disk usage. And that can be done in different ways.
 Important factor is percentage of diverse program/SW solutions by games.
There are details on my pages:  https://atari.8bitchip.info/doinadapts.html

So, most is with TOS function calls. That needed making TOS 1.04 running in RAM - what solves multiple things: TOS version incompatibility problems, special hard disk access from game, support for game state saves and exit to Desktop ...
 Needed disassembling properly TOS 1.04 - and that was long process.  First versions were with only GEMDOS part - without AES, Desktop, as most of games is with AUTO run. 

Later I solved AES/Desktop part disasm. too . It is needed for games using TOS AES functions , so windows, menus and functions in second part of TOS .

To make if work faster I combined my older disk access system with HAGA, HAGE systems:
https://atari.8bitchip.info/imprhage.html

All this was lot of work, but resulted in being able to do individual game adaptations much faster.
Plus, did improved TOS versions, which are compatible with old Atari SW, games. Unlike EmuTOS .
Must be because my iTOS is buggy (as everything I do) like old Atari SW is buggy     

[Ronald J. Hall]

Thanks for the explanation Peter. 

[TheNameOfTheGame]

I still have and use iTOS on my quad-TOS STE and I find it very well done with cool and useful features built-in.