hi everybody
what are the differences between the 2launching types of QNX RTP? (I
mean betwwen the one with DMA enabled and the one with DMA enabled).
in addition to this could someone explain me what DMA is?
thx in advance.
bye
malv
DMA - Direct Memory Access
PIO - Processor I/O
When using DMA to transfer data from a device, such as a
hard disk, the processor is not needed, except to setup
the transfer. Using PIO, the processor must read each
byte or word of data from an I/O port.
DMA for EIDE controllers is faster, and it uses less
cpu cycles, so it is prefered. However it doesn’t
always work.
Previously, Pascal Malvert wrote in qdn.public.qnxrtp.newuser:
hi everybody
what are the differences between the 2launching types of QNX RTP? (I
mean betwwen the one with DMA enabled and the one with DMA enabled).in addition to this could someone explain me what DMA is?
thx in advance.
bye
malv
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tel;work:0684983171
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adr:;;11bis rue Emilienne;Clamart;;92140;FRANCE
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email;internet:> malvertp@club-internet.fr
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–
Mitchell Schoenbrun --------- maschoen@pobox.com
thank you very much
now I’ve got another question.
what’s a POSIX system?
Mitchell Schoenbrun wrote:
DMA - Direct Memory Access
PIO - Processor I/OWhen using DMA to transfer data from a device, such as a
hard disk, the processor is not needed, except to setup
the transfer. Using PIO, the processor must read each
byte or word of data from an I/O port.DMA for EIDE controllers is faster, and it uses less
cpu cycles, so it is prefered. However it doesn’t
always work.Previously, Pascal Malvert wrote in qdn.public.qnxrtp.newuser:
hi everybodywhat are the differences between the 2launching types of QNX RTP? (I
mean betwwen the one with DMA enabled and the one with DMA enabled).in addition to this could someone explain me what DMA is?
thx in advance.
bye
malv
begin:vcard
n:Malvert;Nicolas
tel;home:0146442377
tel;work:0684983171
x-mozilla-html:FALSE
org:Distributeur Indépendant HerbaLife
adr:;;11bis rue Emilienne;Clamart;;92140;FRANCE
version:2.1
email;internet:> malvertp@club-internet.fr
note:ICQ: 44991708
fn:Malvert
end:vcard–
Mitchell Schoenbrun --------- > maschoen@pobox.com
Previously, Pascal Malvert wrote in qdn.public.qnxrtp.newuser:
thank you very much
now I’ve got another question.
what’s a POSIX system?
POSIX is a standard that came out of the need to standardize
Unix. Back in the good old days there were multiple
versions of Unix, with splits in the development tree. On
top of that there were a number of clones available. Every
version was just a little bit different.
The standard is broken into a number of parts. The basic
standard deals with the programmer interface and some
basic utilities.
Additional parts of the standard deal with optional features
such as realtime, and threads.
Since there is no requirement for the underlying structure of
the OS, it was possible for QNX and other OS manufactorers to
provide POSIX compliance without re-inventing the Unix kernel.
Mitchell Schoenbrun --------- maschoen@pobox.com