caf (04/07/83)
Several announcements have indicated that DOS 2.0 is compatible with DOS 1.1 (proper superset) and programs written for DOS 1.1 will run on 2.0. (Bill Gates: Yes, absolutely! -PC World Vol 1 #1 p. 52) In at least one instance, this is not true! In DOS 1.1, function 1Bh returns a pointer to the current disc's file allocation table along with other some information necessary to calculate the free blocks remaining. (BTW, the DOS 1.1 documenation on this function was incorrect, indicating two different items of information were returned in the same register - See Fig. 1). In DOS 2.0, the pointer only points to the first byte of that table - the rest has disappeared. After spending an excessive amount of time debugging and printing listings (The DOS debugger does not accept program symbols) I finally got the function to work properly, only to find out that DOS 2.0 had a Flag Day for this function. Some other flames about DOS 2.0: The disk buffers do not support read-ahead or write-behind, even tho the IBM hardware is designed to allow this. DOS 2.0 steps the floppies very noisily and seems to cause a disproportionate number of bad sectors. It is necessary to turn verify ON in an autoexec.bat file. However, once this is done, the date/time setting must be done in that file and execution of batch files is still slow. Sorry, you can't put those commands in the config file! Even without disk read errors, DOS 2.0 has an unwelcome habit of corrupting the file system by losing free blocks. It has become necessary to run the disk checker program before any serious work to check on the integrity of the file system. The ANSI terminal emulation is minimal and lacks any editing functions (insert/delete). As far as vi is concerned, it is not much better than an ADM-3a simulation. In addition, some ANSI editing command puts the emulator into some strange 40 column color mode. The edlin editor remains a classic of cruftiness. It still crashes on files without carriage returns. In the same article Bill Gates said: "There's really a lot of dirty software on the market now; we'll have to educate the developers about how to write better software." Judging by DOS 2.0, edlin, and Microsoft Pascal, it would appear that Microsoft will have to look outside their organization for suitable teachers. By 2.12 things should be settled down, but in the meantime, Long live Coherent, Marc and Unix (TM). Chuck Forsberg