Changes
[[Image:HERO-HED.JPG|thumb|192px|Example of FutureOS file header]]Like in [[AMSDOS]] in [[FutureOS]] it's possible to store files in two ways: headerless and with a file-header. :* Headerless files or relocateable files are often files which need to fit exactly into an 16 KB block(f. e. expansion RAM), but don't need to be located in a specific RAM block. * Applications and Executables normally have a file header. The file-header for FutureOS is strongly expanded compared to Amsdos, but fully compatible. It consists of 128 bytes and contain the following data:
Byte(s) ! meaning, function
--------!------------------------------------------------------------------ 00 ! Usernumber of file &00..-&FE, &E5 for deleted entry. Don't use &FF!
01 - 08 ! Filename (8 bytes) (fill unused char with spaces)
09 - 0B ! Extent (3 bytes) (fill unused char with spaces)
* Therefore a graphic-icon uses only 4 * 3 * 8 = 96 bytes from the 99. The remaining three bytes can be used freely.
To calculate the checksum just add all bytes from 00 up to and including byte 66 together. The checksum is then placed to bytes 67 and 68, LSB first.This way there is compatibility to Amsdos.
This is only a summary. All details are in the FutureOS manual, page 41-42.
