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or the memory is not very good at remembering its manufacturer.
Luc Pattyn [Forum Guidelines] [My Articles]
this weeks tips:
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Hi All,
I am writing an application which checks LPT signal for doing something. My code looks like:
void LPTThread()
{
while (1)
{
if (ReadLPT(pinX) = signal level Y) {do something;}
}
//pin is one of pins of LPT port
//signal level of each pin is 0 or 1 at a time
}
This loop cause the CPU usage always 100%, is there any way to prevent it? Can we catch this change by any event handler, it mean when a change occurs at LPT or, this event handler will be called?
Thank you for your help.
(I have already put this message in the C++ forum first but then I find this should be put in this forum)
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Hi,
I don't know about any LPT event; I would suggest you put a delay in your while loop
to reduce the CPU load it generates.
Sleep(1000); would reduce your checking to no more than once a millisecond
(probably once every 16 to 20 msec, see my timers article), and reduce the CPU load drastically.
Luc Pattyn [Forum Guidelines] [My Articles]
this weeks tips:
- make Visual display line numbers: Tools/Options/TextEditor/...
- show exceptions with ToString() to see all information
- before you ask a question here, search CodeProject, then Google
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Thanks for your reply.
My problem is the application must be sure that when LPT signal change, the application will handle it immediately, so that I cannot let my thread sleeps.
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FYI:
I have no experience with LPT (my PC does not even have one), but since 2.0 .NET
supports the serial port through SerialPort class; it has a PinChanged event catching
changes in CD, CTS, DSR, and RING.
Luc Pattyn [Forum Guidelines] [My Articles]
this weeks tips:
- make Visual display line numbers: Tools/Options/TextEditor/...
- show exceptions with ToString() to see all information
- before you ask a question here, search CodeProject, then Google
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I cannot help you with the LPT port but I couldn't help but notice that you want to get the PC to repond very quickly to an external event - I am concerned this may be a problem for you.
The operating system on the PC means that if it is busy doing something else your thread may not get any processor time for several ms. I have written an application that tried to take samples every 100ms and it was very tricky. I could get it to be accurate most of the time, but not ALL the time. You will need to give your thread the highest priority.
If you cannot even wait 1ms for the PC to respond you may have a problem - you may want to reconsider your system design / external hardware since the PC operating system is not really suitable for real time applications.
Best of Luck,
Ali
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Hi folks
I am not a very technical person.
Hope you can help me solve this problem.
I have an electronic thermometer that gives an analog output. I want to display the temperature on my computer in ANALOG form ( a circular dial type display ).
How do I do this. Do I need any special input card and software. And where can I source for this.
I am using Windows XP o/s.
Thank you so much.
John
Pluto7
Pluto7
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Pluto7 wrote: I am not a very technical person.
You're in trouble with this project then...
Pluto7 wrote: I have an electronic thermometer that gives an analog output. I want to display the temperature on my computer in ANALOG form ( a circular dial type display ).
How do I do this. Do I need any special input card and software.
Yes, you need specialized hardware to interface with this device. You may NOT be able to use it though. If you're not a "technical person", you may not even have the minimum knowledge to ask the right questions of a supplier.
This is not going to be cheap. It's probably going to cost you a couple of hunder dollars. You can start looking here[^]. Their stuff is pretty good and you can get the USB interface required, plus a temperature sensor to connect to it, plus, and this if the VERY important part, a software development kit and drivers so you can write code to talk to it.
As for the analog gauge, you can either write your own or use a third party package that draws gagues for you, like Dundas Gauge[^].
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Thanks Dave for your links.
I am familiar with the hardware parts like Transducers and sensors shown there.
But the software part looks intimidating.
You mentioned that the stuff may cost couple of hundred dollars.
What can I anticipate for this.?
John
Pluto7
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From that site, the library comes with a bunch of samples. The object model in their library is pretty simple. Their support is pretty good too.
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- Hello there. I recently aquired a HP Pavillion 522c desktop computor to program on. It works great, but one problem, I have to defrag 2-4 times a day with heavy fragmentation . This not counting the original defrags after installing about 10 Gigs of software and updates.
- Why does it fragment so easily?
- Can it be fixed?
Hard disk
-Western Digital
-60 GB
~Thanks in advandce
"Shorter of breath,
and one day closer to death." ~Pink Floyd
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Thisita wrote: Why does it fragment so easily?
Fragmentation is caused by writing and deleting lots of files to disk, not by the disk itself.
Thisita wrote: Can it be fixed?
No, not really. But it depends on what your system is doing. Reading/writing lots of files will increase the rate at which fragmentation occurs.
But, fragmentation is a part of everyday life under NTFS. Your probably also worried about something that's very normal. What does the fragmentation report come up with as far as fragmentation %?
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Thisita wrote:
- Why does it fragment so easily?
- Can it be fixed?
It can be possibly be improved. It depends on the hard disk manufacturer and their implementation of S.M.A.R.T.
http://en.wikipedia.org/wiki/S.M.A.R.T.[^]
Most manufacturers these days have added intelligent disk writing to increase chances of writing to contiguous disk sectors. You should go into the BIOS and check if SMART has been disabled. It is possible that HP has hidden this BIOS setting or removed it completely.
As the other Dave has stated, there is no way to completely prevent fragmented disk writes, there are no guarantees.
-Randor (David Delaune)
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Thanks
- Well, it seems SMART capabilities(if any) are hidden, which I always thought were used for warning you about eminent hard disk failure
-Fragmentation is said to be 19%, but the bars that MS gives us are 90% red
"Shorter of breath,
and one day closer to death." ~Pink Floyd
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Look at the report, not the graphics. The graphic bar you see can only show you a very small percentage of the disk space. 19% isn't bad at all.
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how to read data from hard disk using int86() function??i have used the 0x13 interrupt and then passed
0x42 to a.h.ah.but m not too sure of wat m reading
prashant jain malviya national institute of technology
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Ummm, that function doesn't exist in the Win32 API. INT86 and INT86X were part of QBasic 2 and 3, many, Many, MANY years ago.
This is doable using the Win32 API CreateFile and various other functions, but without further details about what you're doing and using, it's difficult to describe.
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actually i am trying to make read the data from a hard disk using dos.i am using dos because of memory requirements.in os after win98 this function does not work.
prashant jain malviya national institute of technology
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I believe 0x26 interrupt was the old DOS absolute disk write. I believe you should look at the Digital Mars compiler, as it still supports dos_abs_disk_write() and other ancient function calls. In addition it supports COFF format and can generate a MS-DOS stub.
http://www.digitalmars.com/rtl/dos.html#dos_abs_disk_write[^]
Best Wishes,
-Randor (David Delaune)
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The problem with using the old DOS functions under WinNT kernels is that, one, DOS doesn't exist anymore (except for a compatibilty box), and two, the functions are off-limits to user mode applications.
I already told you under today's O/S, you have to use the Win32 API to do what you want.
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Not sure if this is the right forum, but I'll give it a try. I've googled this without getting an answer. Does anyone know how to programatically eject a PCMCIA card (In this case a Novatel AirCard)? Does .NET have this functionality, or is there something in the win32 API?
Thanks,
Mel
"We may not be the smartest in the world, but we're the smartest you've got." (a co-worker to our manager)
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I was under the impression that PCMCIA card's had a hardware only locking and ejector system? Or am I thinking of the wrong cards?
They're the ones which you have to push in to release, then the button sticks out a bit and then you have to push it back in to lock it again?
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Sorry. I should have clarified what I meant by "eject". What I want to do is to "stop" the card. The equivalent of clicking on the systray icon and stopping the card for "safe" removal.
"We may not be the smartest in the world, but we're the smartest you've got."
-a co-worker, speaking to our manager
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Ahhh right  uhhh I'd think theres probably an API call for that ... but unfortunatly I have no idea what it would be sorry.
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cant be done.
Truth is the subjection of reality to an individuals perception
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