On Tue, 2003-06-03 at 15:06, Gilad Ben-Yossef wrote: > Gilboa Davara wrote: > > > > > Posix thread library is problematic. > > Here's a couple of examples. > > A. Threads: > > Lack of true, low level, thread control. > > For instance, in Win32 I can save a thread's context, suspend it > > remotely (from another thread or even a controlling process) implant the > > saved context into it, and it'll continue running from the were I > > stopped it. (Kind'a like hardware interrupt) > > ptrace(2) says: > > " PTRACE_PEEKTEXT, PTRACE_PEEKDATA > Reads a word at the location addr in the child's > memory, returning the word as the result of the > ptrace call. Linux does not have separate text and > data address spaces, so the two requests are cur- > rently equivalent. (The argument data is ignored.) > > PTRACE_PEEKUSR > Reads a word at offset addr in the child's USER > area, which holds the registers and other informa- > tion about the process (see <linux/user.h> and > <sys/user.h>). The word is returned as the result > of the ptrace call. Typically the offset must be > word-aligned, though this might vary by architec- > ture. (data is ignored.)" > > The equivilient POKE functions exists as well.
I'll give it a look-see. Thanks! > > > > Under Win32 the thread scheduling is more robust, I've got more levels > > of control between low, normal, and real time. (Without messing with the > > scheduling type, FIFO, RR, etc) > > POSIX provides 100 levels of real time scheduling + a dynamic priority > for normal/low proccess and teh addtional ability to pick the scheduling > algorythm used to pick the next task, changable at run time. > > Care to eloborate which feature are you missing? Actually the number of levels depends on the scheduling type. sched_get_priority_min(SCHED_TYPE) to sched_get_priority_max(SCHED_TYPE) However, (and current me if I'm wrong) the I can't change the scheduling type once the thread is running. At least in my case, I rather have less control over the scheduling algorithm in-order to gain simpler to use "set-priority" function. (Kinda like getpriority and setpriority). > > > > Oh, and the lack of true smart wait function is problematic. (I usually > > create a mutex that goes with a thread to emulate a true thread wait > > function.) > > What is the additional features which the smart wait function provides > above a mutex? Section E... > > > > > B. Events (posix conditions). > > Wait it doesn't work right (PulseEvent never did... MS, like MS, just > > refuses to fix it), NT events are much easier to use, and have much > > better control. The posix conditions are a just pain in the back side. > > I don't understand the issue, so I'll jsut shut up... posix condition require an external mutex lock, they cannot operate in flood-gate mode. (only single pass). > > > > > C. Process. > > fork + exec, is far less effective and feature rich then CreateProcess > > (Or, CreateProcessAsUser, etc) > > How much of that added functionality is ever used in 99.5% of the uses > of that function? how many programers understnad the model involved? > Someone here (Shachar) said here that it's more of mentality issue. I rather use a single command for everything. Posix, requires a set of commands to achieve the same target. (create attribute, change attribute, apply attribute to new thread/process/mutex/condition, use object) while the Windows API does the same, using flags, in the main create function. > > > > > D. Process, Thread control. > > Lack of Affinity mask (Ability to divert a single process / thread to be > > used on CPUn,y,z outside the OS's discretions) > > CPU affinity is available under Linux, at least. > If you can find me the command, I'll be forever in your debt. I googled myself to death over this one. > > > > > E. Wait functions. > > WaitForSingleObject (WaitForMulitpleObjects) is by far better then > > anything posix. The ability to create a single wait that will work on > > threads, processes, files, events, mutexes, etc, is a true blessing. > > I'm currently looking into ways to emulate the WaitFor* on posix > > machines. > > > > Yes, you're right there. Will you release the code as GPL when you're > done? :-) Sure! > > Yes, Microsoft have in their time, done a lot of very good things and > some pretty stupid ones. What made me leave the M$ world and turn to > Unix/Posix/Linux as that i didn't like the need to rel-earn everything I > knew every 2 years. It's tuff to learn Unix, but once you do you can use > the knowledge for years. I did not expreince this under the M$ regime > and it can even be claim that it's by design. I don't doubt it. My first posix machine was an old HP-UX, then SCO (Tpu!) Unix, DEC, Solaris and now Linux. I wrote posix code well before I ever wrote a single Win32 line... > > > Gilad -- Take care, Gilboa Davara XML - Systems Israel. mailto:[EMAIL PROTECTED] ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
