DIET (compression) - Revision history

Jsummers: /* Software */ Better link

2025-03-27T14:01:50Z

‎Software: Better link

Jsummers: /* Software */

2023-12-29T17:51:46Z

‎Software

Dexvertbot: /* Sample files */

2023-12-28T04:13:18Z

‎Sample files

Jsummers at 15:34, 19 August 2023

2023-08-19T15:34:33Z

Jsummers: /* Identification */

2023-08-19T15:30:57Z

‎Identification

Jsummers: /* See also */

2023-08-12T13:00:34Z

‎See also

Jsummers at 18:49, 7 August 2023

2023-08-07T18:49:00Z

Jsummers at 15:22, 4 August 2023

2023-08-04T15:22:49Z

Jsummers: /* Software */

2023-02-13T16:36:52Z

‎Software

Jsummers: /* Software */

2022-09-19T15:38:44Z

‎Software

@@ Line 96: / Line 96: @@
 * {{CdTextfiles|swextrav1993/disk3/assorted/diet10.zip|v1.00}}
-* v1.00d: [https://archive.org/details/tekno-6-1998 TEKNO 6-1998] → DEMOER/GRAVITY3/PC_4KB/SPARK.ZIP → SRC_NORM.ZIP → DIET.EXE
+* {{CdTextfiles|astra/ts/12a/diet1d.zip|v1.00d}}
 * [https://archive.org/details/msdos_shareware_fb_DIET102B v1.02b]
 * {{CdTextfiles|microhaus/mhblackbox3/ARCHIVER/DIET110A.ZIP|v1.10a}}

@@ Line 93: / Line 93: @@
 == Software ==
-* DIET
+DIET:
-** {{CdTextfiles|swextrav1993/disk3/assorted/diet10.zip|v1.00}}
-** v1.00d: [https://archive.org/details/tekno-6-1998 TEKNO 6-1998] → DEMOER/GRAVITY3/PC_4KB/SPARK.ZIP → SRC_NORM.ZIP → DIET.EXE
-** [https://archive.org/details/msdos_shareware_fb_DIET102B v1.02b]
-** {{CdTextfiles|microhaus/mhblackbox3/ARCHIVER/DIET110A.ZIP|v1.10a}}
-** {{CdTextfiles|garbo/PC/EXECOMP/DIET120.ZIP|v1.20}}
-** {{CdTextfiles|ftp.wwiv.com/pub/COMPRESS/DIET144.ZIP|v1.44}}
-** {{CdTextfiles|pdos9606/ARCHIVER/EXECOMP/DIET145F.ZIP|v1.45f}}
-** {{OldskoolDOSEXE}} → Executable Tools Pack → packers/diet.*
-** [http://old-dos.ru/index.php?page=files&mode=files&do=show&id=141 Various versions at old-dos.ru]
-For other utilities that may decompress DIET-compressed executables, see [[Executable compression#Decompression software]].
+* {{CdTextfiles|swextrav1993/disk3/assorted/diet10.zip|v1.00}}
 == Sample files ==
 * {{DexvertSamples|archive/diet}}

← Older revision		Revision as of 04:13, 28 December 2023
Line 107:		Line 107:

	== Sample files ==		== Sample files ==
−	* ~~https://telparia.com/fileFormatSamples/~~archive/diet/	+	* {{DexvertSamples\|archive/diet}}

@@ Line 13: / Line 13: @@
 == Technical notes ==
 Researchers should note that DIET's behavior depends on the cluster size of the relevant filesystem. Use the <code>-B</code> option (introduced in v1.10a) to turn off this feature, or else DIET will probably decide not to compress most of your files.
 == Identification ==

@@ Line 15: / Line 15: @@
 == Identification ==
-EXE files usually have ASCII "{{magic|diet}}" at offset 28.
+For what it's worth, the newer versions of DIET detect compressed files by searching for the byte sequence {{magic|0x9d 0x89}}, and ASCII "{{magic|dlz}}", in the first 126 bytes of the file. Both must appear, in that order. This works for the newer formats, but not for all of the older ones.
-The newer versions of DIET (e.g., v1.45f) detect compressed files by searching for the byte sequence {{magic|0x9d 0x89}}, and ASCII "{{magic|dlz}}", in the first 126 bytes of the file. Both must appear, in that order. This works for most DIET-compressed formats, but not for all of the older ones.
+=== Identification of EXE files ===
-v1.44-1.45f: For an EXE file, the sequences are at offsets 18 (the checksum field -- refer to [[MS-DOS EXE#Header structure]]) and 108. For a COM file, the offsets are 10 and 65. For a data file, the offsets are 4 and 6.
+Some DIET-compressed EXE files have {{magic|9d 89}} in the EXE checksum field at offset 18 (refer to [[MS-DOS EXE#Header structure]]), and some have ASCII "{{magic|diet}}" in the unused bytes at offset 28. These signatures might be less reliable than other means of identifying DIET format, as they could be modified.
-v1.20: For an EXE file, the offsets are 18 and 87. For a data file, the offsets are 0 and 2.
+Also, be aware of [[LGLZ]] format, which can be mistaken for DIET.
-A possible signature for v1.20 (and v1.00) COM files is {{magic|fd f3 a5 fc 8b f7 bf 00 01 ad ad 8b e8 b2 10 e9}} at offset 17.
+Let "<code>8e db 8e...</code>" be the byte sequence {{magic|8e db 8e c0 33 f6 33 ff b9 08 00 f3 a5 4b 48 4a}}.
 == See also ==

@@ Line 26: / Line 26: @@
 == See also ==
 * [[LGLZ]]
 * [[PACK (NoddegamrA)]]

@@ Line 3: / Line 3: @@
 |subcat=Compression
 |subcat2=Executable compression
-|released=1990 (beta), 1991
+|released=1990<!-- The first non-"test" version might have been 1991, but test versions are not clearly marked as such. -->
 }}
 '''DIET''' is an executable compression and file compression utility for DOS, developed by Teddy Matsumoto. It does executable compression of [[MS-DOS EXE|EXE]] files (to EXE) and [[DOS executable (.com)|COM]] files (to EXE or COM).
@@ Line 12: / Line 12: @@
 == Technical notes ==
-Researchers should note that DIET's behavior depends on the cluster size of the relevant filesystem. Use the <code>-B</code> option to turn off this feature, or else DIET will probably decide not to compress most of your files.
+Researchers should note that DIET's behavior depends on the cluster size of the relevant filesystem. Use the <code>-B</code> option (introduced in v1.10a) to turn off this feature, or else DIET will probably decide not to compress most of your files.
 == Identification ==
@@ Line 30: / Line 30: @@
 == Specifications ==
-* [https://archive.org/details/msdos_shareware_fb_DIET102B DIET v1.02b] → DIETTECH.DOC
+* [https://archive.org/details/msdos_shareware_fb_DIET102B DIET v1.02b] → DIETTECH.DOC [Possibly an unfinished draft -- lots of errors.]
 == Software ==
 * DIET
 ** {{CdTextfiles|swextrav1993/disk3/assorted/diet10.zip|v1.00}}
 ** [https://archive.org/details/msdos_shareware_fb_DIET102B v1.02b]
 ** {{CdTextfiles|microhaus/mhblackbox3/ARCHIVER/DIET110A.ZIP|v1.10a}}

← Older revision		Revision as of 15:22, 4 August 2023
Line 24:		Line 24:

	A possible signature for v1.20 (and v1.00) COM files is {{magic\|fd f3 a5 fc 8b f7 bf 00 01 ad ad 8b e8 b2 10 e9}} at offset 17.		A possible signature for v1.20 (and v1.00) COM files is {{magic\|fd f3 a5 fc 8b f7 bf 00 01 ad ad 8b e8 b2 10 e9}} at offset 17.
		+
		+	== See also ==
		+	* [[LGLZ]]
		+	* [[PACK (NoddegamrA)]]
		+
		+	== Specifications ==
		+	* [https://archive.org/details/msdos_shareware_fb_DIET102B DIET v1.02b] → DIETTECH.DOC

	== Software ==		== Software ==