file extension ACU

ShrinkIt is a utility program for archiving files and disks. "Archiving", in this usage, refers to the process of placing files or disks "within" another file -- the archive file. Archiving is usually done to prepare the files/disks for transmission via modem, or for storage purposes. Thus, an archive file, whether created with ShrinkIt or another archiving utility, will be a file which serves as an envelope, containing one or more other files, or complete disks. There are a number of reasons for archiving files before transmitting them with a modem. The principal reason is that an archive provides a means of sending the "attributes" of a file -- its filetype and other information -- along with the file itself. An archive also allows several related files (or an entire disk) to be packed together into a single file. True archiving utilities will also have the capability of compressing the files they contain to minimize the transmission time and disk space the archive requires.

ShrinkIt uses a highly efficient compression algorithm known as dynamic LZW, and creates archive files with a format called NuFX. For technical documentation of the format of NuFX archives, refer to the File Type Note for filetype $E0, auxtype $8002. (File Type Notes are available from Apple Programmers and Developers Association.) ShrinkIt and ShrinkIt-GS are currently the standard archiving utilities for Apple II telecommunications. ShrinkIt can unpack files which have been archived with ShrinkIt, as well as those which have been packed with certain other file-packing utilities, such as BLU and ACU.