TTCOMP

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|formattype=electronic
 
|formattype=electronic
 
|subcat=Compression
 
|subcat=Compression
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|extensions={{ext|ttc}}, others
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|released=≤1993
 
}}
 
}}
'''TTComp archive''' is a compressed file format. It was apparently used by some software installation utilities.
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'''TTCOMP''' is the informal name of a file compression utility developed by SWFTE International. Its compressed file format is just a raw blob of [[PKWARE DCL Implode]]-compressed data. The name "TTCOMP" has sometimes been used (misused?) for any file compressed in such a manner, even if it has nothing to do with the TTCOMP software.
  
It uses [[Shannon–Fano coding]] for data compression. It is probably identical, or nearly identical, to [[ZIP]]'s obsolete "IMPLODE" compression method.
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The software is included in SWFTE's ''Typecase'' product, and maybe some other SWFTE products, as files named "COMPR.EXE" and "DECOMPR.EXE". It may also found by itself, as files named "TTCOMP.EXE" and "TTDECOMP.EXE", though there's no evidence that this is an official distribution. The origin of the name "TTCOMP" is unknown; Typecase does not appear to use it. Someone may have derived it from the '''.TTC''' filename extension that Typecase uses for compressed [[TrueType]] fonts.
 
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Though it may be called an "archive" format, it appears to store nothing more than a stream of compressed data.
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== Identification ==
 
== Identification ==
The first byte of a TTComp file indicates the type of compression:
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Refer to [[PKWARE DCL Implode#Identification]] for how to identify PKWARE DCL Implode format in general.
* <code>0x00</code>: binary compression
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* <code>0x01</code>: ASCII compression
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The second byte of a TTComp file specifies the size of the dictionary as follows:
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TTCOMP.EXE/COMPR.EXE appears to only ever use binary compression, and a 4K dictionary. But TTDECOMP.EXE/DECOMPR.EXE can decompress all six modes. So you could decide that ''true'' TTCOMP files always start with bytes {{magic|0x00 0x06}}, or you could account for the other modes as well.
* <code>0x04</code>: 1024 bytes
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* <code>0x05</code>: 2048 bytes
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* <code>0x06</code>: 4096 bytes
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Most TTComp files begin with bytes <code>0x00 0x06</code> indicating binary compression and a 4K dictionary.
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Also be aware of [[ZAR (Zip-Archiv)]] format, which can be mistaken for TTCOMP.
  
 
== Software ==
 
== Software ==
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* [{{SACFTPURL|pack|ttcomp.zip}} ttcomp.zip] → TTCOMP.EXE, TTDECOMP.EXE (DOS software)
 
* [http://www.exelana.com/techie/c/ttdecomp.html TTDecomp]
 
* [http://www.exelana.com/techie/c/ttdecomp.html TTDecomp]
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* [https://vetusware.com/download/Typecase%202.60/?id=7021 Typecase v2.60 (at Vetusware)] (Windows 3.x software; compression utilities are for DOS)
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* {{Deark}}
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See also [[PKWARE DCL Implode#Software]].
  
 
== Sample files ==
 
== Sample files ==
* [http://ftp.serdica.org/public/drivers/Modems/BITWARE/VERSION.2/DOS/DISK1/BITFAX/ http://ftp.serdica.org/.../BITFAX/*.??$]
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* [https://archive.org/details/TYPECASE_ZIP Typecase Demo] → *.TTC
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* [https://archive.org/details/UniversalDialUPModemDriverCD Universal Dial UP Modem Driver CD] → SOFTWARE/BITWARE/.../*.??$
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* {{DexvertSamples|archive/ttcomp}}
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[[Category:PKWARE]]

Latest revision as of 05:14, 28 December 2023

File Format
Name TTCOMP
Ontology
Extension(s) .ttc, others
Released ≤1993

TTCOMP is the informal name of a file compression utility developed by SWFTE International. Its compressed file format is just a raw blob of PKWARE DCL Implode-compressed data. The name "TTCOMP" has sometimes been used (misused?) for any file compressed in such a manner, even if it has nothing to do with the TTCOMP software.

The software is included in SWFTE's Typecase product, and maybe some other SWFTE products, as files named "COMPR.EXE" and "DECOMPR.EXE". It may also found by itself, as files named "TTCOMP.EXE" and "TTDECOMP.EXE", though there's no evidence that this is an official distribution. The origin of the name "TTCOMP" is unknown; Typecase does not appear to use it. Someone may have derived it from the .TTC filename extension that Typecase uses for compressed TrueType fonts.

[edit] Identification

Refer to PKWARE DCL Implode#Identification for how to identify PKWARE DCL Implode format in general.

TTCOMP.EXE/COMPR.EXE appears to only ever use binary compression, and a 4K dictionary. But TTDECOMP.EXE/DECOMPR.EXE can decompress all six modes. So you could decide that true TTCOMP files always start with bytes 0x00 0x06, or you could account for the other modes as well.

Also be aware of ZAR (Zip-Archiv) format, which can be mistaken for TTCOMP.

[edit] Software

See also PKWARE DCL Implode#Software.

[edit] Sample files

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