Since DOS environments typically don't multitask, there's no need to time applications as they consume CPU resources and preempt them to let other applications run. Modern multi core processors can do real multitasking and don't have to simulate process concurrency. In DOS environments, there is no multi tasking, so it doesn't make sense to time programs beyond looking at whether the program's time complexity is roughly exponential or not. Is the solution to the problem a polynomial time solution or worse? If you need an idea real time of how your program is using the system's resources, you need UNIX, MACOSX, Windows, or some other modern OS.
I guess there is nothing stopping you from writing multitasking into your DOS based application, think Windows 3.11. If you go to the trouble though of recognizing multiple processes and task switching, chances are good that you'll want to protect user A's processes from meddling by user B. DOS is a lightweight OS because unlike UNIX and Windows NT it doesn't attempt to block direct hardware access let alone provide abstractions for hardware. DOS is lightweight, but DOS applications are hard to maintain. Actually, hard drives and video devices are abstracted in DOS. As hard drives and video devices change, DOS has to change too. VESA is a standard, but is it updated? How about the BIOS which is changing now? There is talk of having to have a special bios and a boot sector signature to run Windows NT, how will that affect Freedos and Linux going forward? Printers and mice for example have changed over time where interfaces have changed beyond just the hard drive interface. Think universal serial bus, a replacement for serial ports, parallel ports, and PS/2 ports. For commercial DOS programs you are very unlikely to be able to use a USB printer with them. USB gamepads and joysticks? Not likely with games themselves having to support the hardware directly. USB video cameras? Again, not likely. DOS environments as far as I know don't even protect against processes accessing memory that doesn't belong to them. DOS originally was QDOS which stood for quick and dirty operating system. No protection means you can write fast programs and not worry about the overhead of protection, but you can't preempt processes to multitask without protection. Aside from simple applications which have to run fast, does Freedos make any sense? Emulated hardware running Freedos or DOSBox make a lot of sense so long as the DOS application of choice doesn't tax a modern computer. Knowing how long a program will take to execute is often important, but Freedos isn't the best environment for real time or otherwise time critical apps. ------------------------------------------------------------------------------ This SF email is sponsosred by: Try Windows Azure free for 90 days Click Here http://p.sf.net/sfu/sfd2d-msazure _______________________________________________ Freedos-user mailing list Freedosemail@example.com https://lists.sourceforge.net/lists/listinfo/freedos-user