Files in Pygmy Forth

Abstract

Pygmy Forth allows simultaneous access to up to 15 DOS files. Each file has its own range of block numbers, thus nothing special needs to be done to switch between files. Pygmy file handling has gone through three stages. I found the first approach (through version 1.2) a pleasant improvement over F83, but not perfect. The current release (version 1.3) solved some problems, but at the expense of a more complicated setup procedure. The next version wit!l keep the functionality and restore the simplicity. File handling is a little too complex in Pygmy Forth version 1.3, so I have worked out a way to simplify it without losing any functionalist y. The following description traces the changes from the first version of Pygmy, through the current release, and beyond. Pygmy is based on Charles Moore’s cmFORTH for the Novix, but with many changes to suit me, the 8088 CPU, and DOS. My goal was a lean, powerful Forth, and Pygmy has met it, to my reasonable satisfaction, especially now that I’ve streamlined the file handling. Pygmy allows up to 15 DOS files to be open, and opened automatically. It does this by assigning different ranges of block numbers to the different files. Thus, any block in any file is available merely by referring to the proper block number. This makes copying between files as easy as copying within a single file, and solves what I feel is the key problem with F83’s file handIing the use of the same range of block numbers to refer to more than one file. Pygmy Permission to copy without fee sll or psrt of this material is granted, provided that the copies are not made or distributed for direct cmnmercisl advantage, the ACM copyright notice and the title of the publication and its date appear, and notice is given that copying is by permission of the Association for Computing Ma&in.ry. TO copy otherwise, O. t. republish, require. . fee and/or speciilc permission. 431991 ACM 0-89791-462-7/90/0200-0121 $1.50 has no need for the OPEN . . . FROM . . . of F83,, as all blocks are simultaneously available. In all the versions of Pygmy, the information for each file is kept in the FILES table. Each line or slot in the table is called a unit. The worcl . FILES prints the name, starting block#, status, etc. of each file in the table.