optical@kuhub.cc.ukans.edu (04/24/89)
Has anyone tried the EZ-DOS 4.1 (by Digital Research & 2001 Sales)? How about the Concurrent DOS? I would like to obtain more info. on these products from actural users. Thanks in advance! Qiwu Liu Computer Center Univ. of Kansas
bcw@rti.UUCP (Bruce Wright) (04/29/89)
In article <5685@kuhub.cc.ukans.edu>, optical@kuhub.cc.ukans.edu writes: > Has anyone tried the EZ-DOS 4.1 (by Digital Research & 2001 Sales)? > How about the Concurrent DOS? I would like to obtain more info. on > these products from actural users. > I have never used EZ-DOS, but I have done a fair amount of playing around with Concurrent DOS. Concurrent DOS is a reasonable multitasking implementation of a DOS-like environment. As you might imagine, true DOS compatibility is limited, if by that you mean can it run XYZ hostile PC application (sometimes it seems that this means 95% of them ...). It can't run most game programs, for example, and Sidekick and similar abominations give it fits. It is rather nice to be able to edit in one window while a compile or whatever is running in another window. (Unfortunately if you like MAC-like windows, the Concurrent windows are text based rather than graphics based). Generally compilers work, and a fair number of editors work (I doubt, for example, that Brief would work -- I've never used the editor but judging from what I've heard about how much it likes to bypass the OS I doubt that Concurrent would tolerate it well. Also it is unlikely that Microsoft Word would run for similar reasons). There is a reasonable editor that comes with it, and numerous places sell editors that WILL run on it - notably VEDIT, there may be others. Early versions had compatibility problems with the batch files and with the ANSI terminal emulation that made it much less DOS compatible than you might think it could be, but that problem has been pretty much cleared up. You do pay for having a multitasking environment - the operating system takes up around 256K+/- (depending on which version and what options you have installed). The tasking efficiency is fair. The versions I have played with are not real great with overlapping disk processing - the file system handler is single-threaded; if one process has the disk semaphore, nobody else can do any disk I/O until that process has released it (this happens at the operating system level and is transparent to the application programmer or the user, except for the effect that disk I/O is slower than it could be. One consequence of this is that hard disk I/O and floppy disk I/O can NOT be overlapped!!! - the reason I'm aware of the way it works in this detail in fact is that at one time I did a fair amount of XIOS hacking [the Concurrent DOS equivalent of a BIOS] to support some disk drives that DRI in their wisdom did not support). Fortunately this problem rarely occurs in practice - it's more of an annoyance than anything else. Most of the time it really IS a great help, and most of the time you don't get more task-to-task interference than with most other multitasking operating systems (most of them don't handle two applications hitting the same disk at the same time very nicely either -- it's not an easy problem to deal with). It is also VERY nice to have a DOS-like operating system with a REAL printer spooler instead of the joke that Microsoft inflicts on an unsuspecting public. Now for the bad news. The progressive versions of Concurrent DOS have deteriorated after version 5, and the current version of Concurrent DOS will not run on my PC. Since I do not have a license for the XIOS (the XIOS hacking was for a customer who needed it modified & who owned the license for it), I am unable to find or fix the problem (at least not without a great deal of trouble, especially since my experience with the XIOS was several versions back), which I suspect to be in the video support (windowing crashes the system in funny ways). If it can run your applications and if it can run on your machine, I think it is a reasonable environment. I'd suggest trying to find someone who already has it and trying it out since DRI is not a particularly responsive company ..... Bruce C. Wright