The modes

The modes: how the adaptations reach their files

The hard-disk adaptations on the 8bitchip.info website start their games in a few ways, called modes here. For each mode this page gives the files that mark it, how the game reaches its files while it runs, and what happens on a GEMDOS drive. A GEMDOS drive (Hatari's --harddrive, the Multidevice's GEMDRIVE) serves files by name and has no sectors, the numbered blocks of a disk. The facts come from the website's documentation, the files of its 1,947 archives, and one Hatari run per mode (§8). The verdicts in §4 are first guesses; solutions.md has the results of running every game.

1. Two ways the games are sorted

The 8bitchip.info website sorts the games into six categories by how the original game used the floppy (§2). This page sorts the adaptations into modes by the launcher, the program the user runs (START.TOS or RUNME.TOS) (§3). The category says how much work the adaptation needed. The mode says how the adapted game reaches its files, and so whether it runs from a GEMDOS drive:

• By name. The game asks GEMDOS, the part of TOS that handles files, to open a file. Every drive serves that, a GEMDOS drive included.
• By sectors. The game, or a GEMDOS in RAM that it brings, reads the disk's sectors through a hard-disk driver. A GEMDOS drive has no sectors to give.

2. The six categories and the Cat: code

agcat.html, "Atari ST game categorisation by hard disk run possibility - way how to solve it", was written after "adapting about 450 Atari ST(E) games". The quotes below are from it.

GOS, HOLE and the Floppy Image Runner are described in §3.3 and §3.5.

Each game page gives its category as a code, such as Cat: M5TPL. The letters, as agcat.html defines them:

The game pages use more letters. A goes with "TOS/AES dep" (M5ATPL, 41 pages), E with "AES dependant" (M5EPL), X with the XBIOS loaders of category 5 (M5TX8, Alternate Reality, listed there). DFC (M5DFC, 97 pages) is explained nowhere on the website. 1,609 of the 1,829 game pages carry a code. The most common are M5TPL/M1TPL (908), M#IF (253), M#DFC (97), M#TL (80) and M#ATPL (41). 108 codes start with S.

Category 6 is the expensive one. The documentation's "best" answer to it, GOS and a hard-disk driver in high RAM, reads the disk by sectors: it is the mode that does not run from a GEMDOS drive (§3.3).

3. The modes, from a game's files

The files in a game's folder show its mode. Each of the 1,947 archives is counted once, in the first row it matches; recognising-modes.md counts games instead.

The names in the table:

• Gamex ("gaming extra") adds an exit to the desktop and state saves. Its utility is GXUTnnn.PRG.
• GOS is TOS 1.04's GEMDOS 0.15, modified, loaded into high RAM before the game. Its builds are the D15R… files: GOS 1.00, GOS4, GOS5, and those of the HAGA family.
• HAGA, HAGE and HAG2 are the shared modules of the adaptations made since January 2012, the HAGA family.
• T14 files hold TOS 1.04 itself, for HAGE and HAG2. §5 says how much of each D15R and T14 file is TOS 1.04.

What the launchers share. Every Gamex launcher unpacked here (Lemmings, Magnetik Tank, Clever & Smart, Bubble Dizzy, Garfield, Castle Master) has the frame of the three published launcher sources: the hardware screen ("Machine:", "TOS RAM:"), the RAM checks ("Too much low RAM occupied", "Min RAM"), the Mega STE clock and the Falcon bus and cache settings (not in Garfield's), the cover picture (a .PCH file), the Gamex id PPGX and the same unpacker. They differ in how they read the game's files and, before 2012, in the driver checks (§3.3). In the HAGA family the frame moved into the module (HAGA and HAGE hold the hardware screen, the settings and the unpacker) and into RUNME.TOS (the RAM messages). Recoil's START.PRG, a launcher without Gamex, has only the unpacker.

3.1 HAGA (since January 2012)

The files. RUNME.TOS, the module HAGA, the game's data in FILES\ and, in most games, a GOS. Of the 1,108 HAGA archives, 357 have D15RH.FIC and D15RF.FIC, 297 have D15RU.FIC, 447 have no GOS and 7 have D15R_5H/5F. The shared files (D15R*, D15RU.FIC, HAGA, HAGE, HAG2, T14AG.FIC, T14GG.FIC) may be kept once, in C:\GAMEX (GamexUsage.html, fromhd2.php). Only 82 of the 1,108 HAGA archives carry a floppy image.

The documentation promises any driver. fromhd2.php: "Earlier adaptations, before Jan. 2012 work only with mine drivers, AHDI, and Seimet's Hddriver. Later ones, where you can see file HAGA or HAGE, HAG2 in root folder of game will work with any decent driver". fromhd3.php tells beginners to take adaptations "done after date Jan. 13 2012 … They work well with all decent hard disk driver SW, in emulators." Its state saves are programs: "File with name GSxx.TOS will be created … Yes, it is runnable !"

How it starts, from Wormhole's files (WORMHOLE.ZIP, May 2020):

• RUNME.TOS, a plain GEMDOS program of 1,515 bytes, reads HAGA from the game folder, or else C:\GAMEX\HAGA, and copies it to the top of RAM ($F8000 with 1 MB).
• HAGA is about 13 KB of code of its own (0.4% of it is found in TOS 1.04). It starts with a table of 16 word offsets to its entries: hardware detection, the Mega STE, Falcon and TT settings, the cover, the start, the state saves (GSAU.TOS, GSxx.TOS), the hooks and the file service (entry 4). It also checks for PPDRIVER (PPHD), as Lemmings' launcher does, and handles the disk vectors. It exists in 25 versions; the two most common cover 912 of its 1,109 copies.
• D15RU.FIC is a GOS: TOS 1.04's BIOS, XBIOS and GEMDOS in RAM, 89,632 bytes unpacked (the game pages: "new HAGA file with single D15R* (TOS 1.04 in RAM) solution"). It starts before the game, for the game's TOS calls. By their names, D15RH/D15RF are an ST and a Falcon build, as D15R_H5/F5 are (launch-chain.md).

How the game reaches its files. Through HAGA's file service. The game hands it a parameter block: a buffer, an offset, a length, a mode word ('cR' or 'Wr') and a name. The service saves the game's state, calls the machine's GEMDOS (Fopen or Fcreate, Fseek, Fread or Fwrite, Fclose), and gives the game its machine back. The data is in the adaptations' packed format, several streams to a file: Wormhole's FILES\WHD holds DATA1.DAT to DATA5.DAT.

On a GEMDOS drive it runs. Wormhole reaches its title from the GEMDOS drive (run 20261011-190920) and from PPDRIVER (20261011-190812):

• From the GEMDOS drive, Hatari serves every file by name: HAGA, WHLA, D15RU.FIC, WHD. WHD is opened from HAGA's own code (PC $F902C, its copy at $F8000).
• From PPDRIVER, the same Fopens become TOS's own Rwabs on drive C (PC $FC9206, the ROM).
• The only sector reads from the GEMDOS drive are GOS's, when it starts: Getbpb(0) and two Rwabs on drive A, which has no floppy. GOS carries on. The documentation: "keep some floppy disk in your floppy drive A … Important mostly for earlier adaptations".

Quest for Galaxia (HAGA with D15RH) and Andromeda (HAGA, no GOS) behave the same.

3.2 HAGE and HAG2

The files. The module, a TOS 1.04 to load into RAM, and the game's original floppy as an image file in FILES\:

• HAGE loads T14AG.FIC: 179,269 bytes unpacked ("T14AGH22.TOS"), TOS 1.04 from $FC0000 to $FEC000, GEM included. Breakout ACC's page: "TOS/AES dep … HAGE-fying", M5ATPL.
• HAG2 loads T14GG.FIC: 87,363 bytes unpacked ("T14G16.TOS"), the BIOS, XBIOS and GEMDOS only, like the D15R files.
• HAGE and HAG2 (12,394 bytes each, most common versions) differ in 11 bytes: their own name, the TOS file they load (C:\GAMEX\T14AG.FIC or C:\GAMEX\T14GG.FIC, and FILES\… in the game) and its size.

215 of the 219 HAGE archives and all 141 HAG2 archives carry the image.

How the game reaches its files. The game runs on the TOS in RAM and reads its floppy, drive A, by sectors. The module serves those reads from the image file, which it reads by name with the machine's GEMDOS.

On a GEMDOS drive it runs. In Breakout ACC (HAGE, run 20261011-192118), TOS 1.04 starts in RAM and reaches its GEM desktop; the game is a desk accessory. TOS's floppy reads are Rwabs on drive 0, from the RAM copy (PC $C4172). Between them, HAGE reads the image FILES\B.ST with the machine's GEMDOS, from its own code (PC $F8FF6): Fread(6144) from the start, then Fseek(12288) and Fread(35328). 180 (HAG2, colour, 20261011-193147) reaches its title the same way, from T14GG.FIC and the image FILES\1.ST.

Vector Invaders needs 2 MB, not the 1 MB its page gives ("Needs monochrome capable monitor", "min 1 MB RAM"):

• With 1 MB it halts, in colour or monochrome, on the ST with TOS 1.04 and the STE with TOS 1.62, from the GEMDOS drive and from PPDRIVER alike (runs 20261011-192209, -192639, -194136 mono, -194301 mono PPDRIVER, -194842 STE mono). After the image's first 6,144 bytes, HAG2 asks for Fseek(-113984) and Fread(193856) into $82800, and an RTE in the RAM TOS takes an Address Error (PC $DA9EA, hatari.log).
• With 2 MB, monochrome, from the GEMDOS drive (20261011-195006), the same HAG2 seeks to 6,144 and the game plays.
• The image is not the cause: a copy whose boot sector's sector count matches the trimmed file (720 → 144) halts the same way (20261011-194559).

3.3 Gamex with GOS4 and GOS5 (before 2012)

The files. START.TOS and a GOS: D15R_HH4.FIC or D15R_F4.FIC for GOS4 (90 archives), D15R_H5/F5, H15/F15 or 5H/5F for GOS5 (33 + 44). Lemmings is one (§7).

GAMEXdoc.html gives the RAM map with 1 MB. GOS4: "768KB-860KB GEMDOS 0.15", "700KB-768KB Hard disk driver, buffers - used while playing game". GOS5: "Modded, reduced GEMDOS 0.15, only for file I/O". GamexUsage.html supports four drivers, PPDRIVER, AHDI, Hddriver and ICD's ("other drivers are not supported"), and in emulators "only when real hard disk emulation is set". fromhd.php, on GEMDOS drives: "some game hard disk adaptations use such functions [XBIOS sector access], and worse: direct hard disk access - that's not present in GEMdrive".

How the game reaches its files. First the launcher makes sure a driver is there. Every GOS4 and GOS5 launcher looked at has the three checks of Lemmings' launcher (launch-chain.md step 7, gemdrive-failure.md):

1. It looks for PPDRIVER's PPHD signature through hdv_bpb, and if it finds it, copies PPDRIVER to $B7180.
2. Otherwise it reads pun_ptr, and reads sector 0 with XBIOS DMAread.
3. It boots the driver found in that sector (the 'DMAr' pattern).

They are in Lemmings' LEMLD2.TOS and in the unpacked launchers of Magnetik Tank (GOS4), Clever & Smart and Bubble Dizzy (GOS5) (§5). The game then reads its files through GOS's GEMDOS, which reads the disk by sectors through that driver (disk-layer.md).

On a GEMDOS drive these games do not start. Magnetik Tank (run 20261011-191703) and Clever & Smart (20261011-191754) load their GOS, ask for the current path and quit (Pterm0) without a message, back to the desktop. Bubble Dizzy (20261011-191845) loads a data file (BUDI.FIC) first, then quits the same way. Lemmings prints This prg. requires PP, AHDI or Hddriver (gemdrive-failure.md).

From PPDRIVER all three play: Magnetik Tank in its first room (20261011-192804), Clever & Smart in play (20261011-192854), Bubble Dizzy at its high scores (20261011-192945). They make 42, 61 and 56 Rwabs calls on drive C, and open no file by name once GOS has started.

3.4 Gamex without GOS, and with GOS 1.00

The files. START.TOS or START.PRG and GXUTnnn.PRG, with no D15R file (120 archives), or, with GOS 1.00, D15R_NG1.FIC or D15R_F1.FIC (7).

The three published launcher sources are one of each kind (astopensw.php: "1: for TPA executables 2: For games not using TOS 3: Using GOS 1.00, for singleparted game"):

• Castle Master (GamexLSrc.html) Pexecs the game's own programs, CASTLE1.TOS and CASTLE2.CTE.
• Sideways (GamexLSrc2.html) is "singleparted + packed": one Fopen of S123.FIC, unpacked into place.
• Starglider (GamexLSrc3.html) installs the "modded GEMDOS 0.15 of TOS 1.04" (D15R_NG1.FIC) in high RAM "and run[s] under GEMDOS 0.15", "AUTO run without reset of ST".

How the game reaches its files. By name, with the machine's GEMDOS. Gamex only adds the exit to the desktop and the state save (GAMEXdoc.html: "Gamex handles not loading of game files, it is on launcher"). Castle Master's and Garfield's (GOS 1.00) launchers, unpacked, have neither the PPHD nor the DMAread check.

On a GEMDOS drive both run, with no sector reads. Castle Master (run 20261011-191521) opens CASTLEM.PCH and CASTLE1.TOS by name and reaches "Choose your character". Garfield (20261011-191612) loads D15R_NG1.FIC, GART.FIC and GASM.FIC by name and plays its intro.

3.5 The rest

• A launcher without Gamex (56 archives): START.TOS or START.PRG without GXUT. Recoil's has only the Gamex launchers' unpacker, reads one packed file (RECCODE.FIC) by name, and reaches its attract screens from the GEMDOS drive.
• HOLE (HOLE.ZIP, plafh.html; 5 archives, and the tool) is not a launcher. It keeps the low 512 KB (or 1 MB) of RAM free for the game, one of the answers to category 4. FBHOLE and SBHOLE write a floppy boot sector that does it before the hard disk boots; HOLE.PRG does it from a floppy's AUTO folder. The game is its own files ("Working games on TOS 2.06, Falcon: Millennium 2.2, Chuckie Egg 2, Monthy Python, F16 Falcon, Aquanaut …"). Aquanaut, started without HOLE (run 20261011-193036): AQUANAUT.PRG Pexecs AQUANAUT.EXE by name and both end at once, back on the desktop. It was not run with HOLE's floppy.
• AUTO (1 archive, not run): the game starts from the AUTO folder (agcat.html category 4; Goal: "run from AUTO folder of boot partition on hard disk").
• The Floppy Image Runner (imgrun.php, IMGRUN3.S) runs a game from an image file: "copy image file in high RAM and restart TOS, then mounting RAMdisk as drive A … Hard disk driver is discarded"; "GEMDos file access and XBIOS A floppy read is mapped to RAMdisk". It opens the image with GEMDOS Fopen and hooks hdv_bpb, hdv_rw and hdv_mediach. IMGRF2X adds TOS 1.04 in RAM (T14UIDUB.FIC, a whole TOS 1.04 ROM). It does not work for "games using direct FDC access". The 13 archives that hold only a floppy image were not run.
• RAM TOS (RAMTOS.ZIP): SELTOS and RAMTOS install a TOS 1.00, 1.04 or 2.06 ROM image in RAM and restart.
• iTOS, an improved TOS (1.04i, 1.62i) with a hard-disk driver inside, from the same website, needs its own GOS (fromhd2.php: "different ones (D15R***.FIC) are needed for improved TOS"). D15RI.FIC ("D15I81.TOS") is in 2 archives; Space Ace's page says it needs iTOS. iTOS is not one of the regular TOS versions ("1.00-4.04") the adaptations support.
• Small tools: HDTCFIX (Hddriver's Timer C fix for some games), 512K_1M (makes a bigger machine act like 512 KB or 1 MB), GXUTnnn.PRG (the Gamex utility: continue, save the state, free RAM). AUTOlist Run (plafh.html: "for easy launch of games (running only from AUTO) from hard disk") was not looked at: its download, ALISTR, answered 404 when the site was copied.

3.6 Plain installations

The files. The game's own program and data, copied to the hard disk, with no launcher, no Gamex and no GOS. This is how the documentation handles the games of categories 1 and 2 (§2): a game that already reads its files through GEMDOS needs only its paths changed from drive A to the folder it runs from ("redirect to hard disk"), and the copy protection removed.

How the game reaches its files. Through the machine's GEMDOS, by name, as on the original floppy. Nothing is loaded before the game.

On a GEMDOS drive. A GEMDOS drive serves exactly that, so a plain installation runs as it is, unless the game does something besides opening files. Of the 123 games, 113 run as they are. The others:

• Four Silmarils games ask BIOS Getbpb for the drive's layout before every file and wait until they get one. A GEMDOS drive has none to give (fix S2, GDBPB.PRG).
• Two start programs give back the memory their stack is in, then start the game. Hatari's GEMDOS drive clears that memory when it loads the game, and the start program ends (fix S3, the fastload bit).
• Great Giana Sisters STE streams its music from a file's sectors through the hard-disk driver during play: not feasible from a GEMDOS drive.
• Three games (Roger, Utopos, Spitting Images) fail in Hatari from the PPDRIVER disk too; their verdict is unsure.

3.7 FWRD RAM disk

The files. One FWRD file holds every file of the game: a directory, then the files. Only two adaptations have one, Pick'n'Pile and Lemmings' second download, LEMMSRD.ZIP ("2MB RAM min"). The documentation calls a RAM disk the "usual way" for games that load during play (playfhd.html).

How the game reaches its files. The start program reads the whole FWRD file into RAM by name, once. From then on the game loads its files from RAM, and the disk is not used.

On a GEMDOS drive. The one read at the start is by name, so it runs as it is. Pick'n'Pile reaches its title, and LEMMSRD.ZIP reaches Lemmings' title menu, from the GEMDOS drive. It needs 2 MB of RAM. Whether Lemmings plays a level this way was not tried.

4. First guesses at the verdicts

Before every game was run (solutions.md), each mode got a guess at the verdict: as it is, fix or not feasible.

So the work to fix is in the Gamex launchers with GOS4 or GOS5, from before 2012 (about 167 archives), not in the HAGA family (about 1,468).

5. Signatures and the GOS builds

launcher-signatures.md ("Other modes") has the byte patterns that mark each mode: the HAGA family's names and module table, the three driver checks of the GOS4 and GOS5 launchers (absent from the GOS 1.00 and Gamex-only ones), the GOS builds' header names, and the TOS-in-RAM files.

How much of each shared file is TOS 1.04, as 16-byte runs found in the UK ROM, without relocation:

6. The glossary

Terms from the list's Note column and from the game pages:

7. Lemmings, the worked example

Lemmings is Gamex with GOS5 (D15R_H5/F5), from before 2012. LEMMINGS.ZIP on the website holds the same 76 files as LEMMINGS/, SHA-256 for SHA-256. Its page says "Added gamex, deprotected, filed, filewise ramdisked" and gives no Cat:. Its launcher has the three driver checks (§3.3, §5). GOS reads its files by sectors, through the copy of PPDRIVER that the launcher carries (disk-layer.md), and from a GEMDOS drive it stops at the check (gemdrive-failure.md). Its first guess is "fix", like the other 166 archives of §3.3.

Its page offers a second download, LEMMSRD.ZIP ("2MB RAM min"): the other Lemmings adaptation, with no GOS and no driver check. It is "filewise ramdisked": every file is in one FWRD file (a directory, then the files), read whole into RAM at the start. playfhd.html calls a RAM disk the "usual way" for games that load during play. Only two adaptations have one: this one and Pick'n'Pile. It reaches the title menu from the GEMDOS drive as it is (recognising-modes.md). Whether it plays a level there was not tried.

8. Sources

• The 8bitchip.info website, read in a local copy (never republished here): agcat.html, GAMEXdoc.html, GamexUsage.html, playfhd.html, plafh.html, fromhd.php, fromhd2.php, fromhd3.php (the list and its help), imgrun.php, astopensw.php, and the 1,829 game pages SCRSH/*.html.
• Its published launcher sources (GamexLSrc.html, GamexLSrc2.html, GamexLSrc3.html) and tools (HOLE.ZIP, IMGRSRC.ZIP, IMGRF2X.ZIP, RAMTOS.ZIP, HDTCFIX.ZIP, 512K_1M.ZIP).
• The file names in its 1,947 archives (games and tools), and the shared files (HAGA, HAGE, HAG2, D15R*.FIC, T14*.FIC), unpacked with tools/unpack.py and compared with the TOS 1.04 ROM.
• One game per mode run as it is from Hatari's GEMDOS drive (ST, TOS 1.04, 1 MB) with src/probes/modes/mode_probe.py <ZIP>: run folders tools/dev/logs/20261011-*-st-104-gemdrive-<game>, and -ppdriver- for the reference.

A statement from the documentation counts here only once a run shows it.

Recognising the modes from the files

Every game in the list on the 8bitchip.info website (1,831 records, src/survey/catalogue.csv) gets a strategy: its mode (modes.md), the way its adaptation reaches the game's files, as the survey recognises it. The strategy is read from the files in the game's download (src/survey/files.csv) and the signatures in its programs, not from a run. python3 tools/survey/classify.py writes it into src/survey/migration.csv. How each strategy does from a GEMDOS drive, and how the ones that fail are fixed, is in solutions.md.

A game gets the strategy of its first download that is a hard-disk adaptation; the others are listed in other_downloads. The counts in §1 are today's. The tables of §2 to §4 count an earlier reading of the list, and differ by up to 7 games per strategy.

1. Twelve strategies, two ways to the disk

A game reaches its files in one of two ways:

• By name, through the machine's GEMDOS, the part of TOS that handles files. Every drive serves that, a GEMDOS drive included: Hatari's, or the Multidevice's GEMDRIVE, which serve files by name from a folder.
• By sectors, the numbered blocks of a disk, through a hard-disk driver. A GEMDOS drive has no sectors (gemdrive-failure.md).

Ten strategies read by name: 1,627 games. Two read by sectors, Gamex with GOS4 and with GOS5: 204 games. Every game has a strategy. Each strategy's first guess at the verdict comes from its mode (modes.md §4); a run of every game then checked them (solutions.md).

1.1 The strategies that read by name

They need only the machine's GEMDOS, unless said otherwise.

HAGA

1,025 games. Marked by the file HAGA, one of the shared modules of the adaptations made since January 2012. RUNME.TOS loads HAGA to the top of RAM. HAGA's file service reads the game's files by name through the machine's GEMDOS. Some games also load a GOS (D15RH/D15RF or D15RU) for their TOS calls: GOS is TOS 1.04's GEMDOS, modified, in high RAM. It needs 1 MB, and any driver behind GEMDOS or none. Guess: as it is (modes.md §3.1).

HAGE

207 games. Marked by the file HAGE, T14AG.FIC and a floppy image. HAGE loads TOS 1.04 with GEM into RAM (T14AG.FIC). The game's floppy is an image file (FILES\X.ST), which HAGE reads by name. Guess: as it is (modes.md §3.2).

HAG2

134 games. Marked by the file HAG2, T14GG.FIC and a floppy image: HAGE with TOS 1.04 without GEM (T14GG.FIC). Guess: as it is.

Gamex

110 games. Marked by GXUTnnn.PRG and the START stub, with no D15R file. The stub is the short code at the start of START.TOS that unpacks the launcher and starts it (launcher-signatures.md). The launcher loads or starts the game's files by name. Gamex adds the exit to the desktop and the state saves. Guess: as it is (modes.md §3.4).

Gamex + GOS 1.00

5 games. Marked by D15R_NG1.FIC or D15R_F1.FIC, and no driver checks. The launcher reads by name, then runs the game under GOS 1.00. Guess: as it is.

Launcher without Gamex

18 games. Marked by the START stub and no GXUT. It reads by name. Guess: as it is, likely.

FWRD RAM disk

1 game, Pick'n'Pile. Marked by a file that starts with FWRD. Every game file is in that one file, read into RAM at the start, as in Lemmings' second download. It needs 2 MB. Guess: as it is.

Plain

123 games. With no launcher stub: the game's own program, its paths fixed ("redirect to hard disk"). Guess: as it is, likely, unless the game reads sectors itself (§3).

Plain + HOLE

3 games. Marked by FBHOLE.PRG or SBHOLE.PRG: plain, with the low 512 KB of RAM kept free by HOLE's boot floppy. It needs the HOLE boot sector too. Guess: as it is, with HOLE.

Floppy image

1 game, Ice and Fire. Its download holds only a .ST or .MSA image, for the Floppy Image Runner or a floppy. It needs the Image Runner, which opens the image by name and makes it drive A (modes.md §3.5). Guess: open.

1.2 The strategies that read by sectors

Gamex + GOS4

117 games. Marked by D15R_HH4.FIC or D15R_F4.FIC, and by PPHD, DMAread and 'DMAr' in the launcher. The launcher copies PPDRIVER, or boots the disk's own driver from sector 0. GOS then reads the game's files by sectors through that driver. It needs PPDRIVER, AHDI or HDDriver on ACSI (or IDE, Falcon), found by the launcher's driver checks. Guess: fix (modes.md §3.3).

Gamex + GOS5

87 games. Marked by D15R_H5/F5, H15/F15 or 5H/5F, and the same checks: GOS4's way with GOS5, a reduced GEMDOS "only for file I/O". Lemmings is one. Guess: fix.

2. Set against the 8bitchip.info website's categories

Each game page gives a category code (modes.md §2), read from the list into the code_category column of catalogue.csv. This table counts each strategy's games by category:

What the table shows:

• GOS5 was the adaptations' answer to category 6, games that drive the floppy controller during play: 73 of its 87 games.
• GOS4 went to the file-system games bound to low RAM, categories 1–2 and 4, as agcat.html says: "Work under higher TOS versions is solveable with Image Runner or GOS 4".
• HAGA covers every category, category 6 included (179 games). Since 2012, the same file service replaces the floppy loads of the games that load during play.
• HAGE and HAG2 are file-system games (categories 1–2) that need TOS 1.04 itself, with GEM (A, for AES, in the code) or without.

3. What the programs show

The access column gives the strongest disk access found in the programs the user starts. The START stub is unpacked first, and only text sections are searched, at even offsets. From the strongest:

• registers: the DMA and floppy-controller registers at $FFFF8604-$FFFF860D;
• sectors: XBIOS Floprd or DMAread, or BIOS Rwabs;
• files: GEMDOS file calls only.

The patterns are in launcher-signatures.md ("Disk access").

A hit is a place to look, not a verdict. The runs settle each game (solutions.md).

• GOS4 and GOS5. Every one of their launchers has the PPHD check. 202 of the 203 also have the DMAread fallback and 'DMAr'. Defender 2's GOS4 launcher checks PPHD only.
• HAGA with registers (18 games). 7 of them are the disk-streaming games of January 2012 (Dragon's Lair I, II and III, Escape, Space Ace I and II, Galaxy Force). Their folder keeps the 2010 GOS5 START.TOS next to the new RUNME.TOS. The download's READ_NEW.TXT says "Run with RUNME.TOS" and "Tested with Steem - STemDOS", Steem's GEMDOS drive. The other 11 (Eye of Horus, IK+, No Buddies Land, Pro PowerBoat Simulator, BeastLord, Elvira the Arcade Game, Microprose Golf, Infestation, Disc, Vroom, Maupiti Island) have floppy-controller code in their RUNME.TOS. IK+'s, for example, writes a command to the floppy controller and waits for the MFP to signal that it is done.
• HAGA with sectors (3 games). Lure of the Temptress, Cannon Fodder and Operation Wolf call Rwabs or Floprd.
• Plain. The 13 plain games with sectors or registers, and the 35 whose programs show nothing because their code is packed, are the plain games most likely to read the floppy themselves.
• Inside the packed files. The inner_evidence column lists the same signatures in the download's packed files, unpacked: the game's own stages, without the D15R and T14 files. 164 HAGA games and Lemmings (LS2DD.FIC) have floppy-controller code there. It is the games' own loaders, which the launchers patch at run time (Lemmings': launch-chain.md).

4. What the runs were to check

• The two ways to the disk: every strategy that reads by name should run from the GEMDOS drive past its first file load, and GOS4 and GOS5 should stop at the launcher.
• 18 games need a monochrome monitor (monitor = mono only), and the harness runs them with --monitor mono. Some games need more RAM than their page gives (Vector Invaders: 2 MB, modes.md §3.2).
• Lemmings has two downloads: LEMMINGS.ZIP (GOS5, the row's strategy) and LEMMSRD.ZIP (FWRD RAM disk, 2 MB), listed in other_downloads.