APL+Win: how to read from native files greater than 2.2 GB? 
Author Message
 APL+Win: how to read from native files greater than 2.2 GB?

In APL+Win, version 3.6.09,  []nread is limited to reading from a startbyte
less than 2*31 (~ 2.2 GB).  Does anyone know how to read a native file from
a startbyte of greater than that limit?

Thanks, Joe.



Thu, 15 Apr 2004 03:02:00 GMT  
 APL+Win: how to read from native files greater than 2.2 GB?


Quote:
>In APL+Win, version 3.6.09,  []nread is limited to reading from a startbyte
>less than 2*31 (~ 2.2 GB).  Does anyone know how to read a native file from
>a startbyte of greater than that limit?

>Thanks, Joe.

This might seem flippant, but it's not supposed to be.

You could split the file into 2 GB chunks.
--
John Sullivan



Thu, 15 Apr 2004 03:11:51 GMT  
 APL+Win: how to read from native files greater than 2.2 GB?
A clumsy way with performance penalty: If you omit the startbyte, the next
read will continue from the end of the previous (at least in Dyalog, an APL+
too if i remember correctly). So do some dummy read ops from the highest
possible startbyte and just discard the result - get the pointer correctly
though.

Or then use the Windows API. There is a complete set of functions for native
file reading; a short glance told me that there is a possibility to use
*offsets* as well, not only absolute startbyte positions. So move to the
correct position by using multiple offsets and maybe reading a dummy byte
here and there.
/ Tomas



Quote:
> In APL+Win, version 3.6.09,  []nread is limited to reading from a
startbyte
> less than 2*31 (~ 2.2 GB).  Does anyone know how to read a native file
from
> a startbyte of greater than that limit?

> Thanks, Joe.



Thu, 15 Apr 2004 09:00:22 GMT  
 APL+Win: how to read from native files greater than 2.2 GB?

Quote:
> Or then use the Windows API. There is a complete set of functions for
> native file reading; a short glance told me that there is a
> possibility to use
> *offsets* as well, not only absolute startbyte positions. So
> move to the correct position by using multiple offsets and
> maybe reading a dummy byte here and there. / Tomas

The Win32 API permits the reading of files using 64 bit pointers... It
may be clumsy, but it certainly works. #N functions were a relatively
recent addition to Dyalog APL, and before that the use of #NA bindings
was a standard (working!) procedure.
--

Homepage: http://come.to/wildheart/

<<<All I Ever Learned, I Learned From Anime: ---
   You can never have enough hair.>>>



Fri, 16 Apr 2004 17:07:57 GMT  
 APL+Win: how to read from native files greater than 2.2 GB?
APL+Win Version 4 supports addressing for read and write of up to
2*52 (4 petabytes) for native files.  This version is to be
released "real soon now".  Preliminary development systems will
be distributed at the APL2000 conference next week.

If your problem is more urgent than that, I suggest you contact the
helpline at (301)-564-5027

/Mark Osborne

Quote:

> In APL+Win, version 3.6.09,  []nread is limited to reading from a startbyte
> less than 2*31 (~ 2.2 GB).  Does anyone know how to read a native file from
> a startbyte of greater than that limit?

> Thanks, Joe.



Sat, 17 Apr 2004 03:57:41 GMT  
 APL+Win: how to read from native files greater than 2.2 GB?
Thanks for that info, Mark.  I'm very e{*filter*}d about some of  the features in
Version 4 and have already contacted the sales dept. -- I was told to look
for it in mid-November.

Joe


Quote:
> APL+Win Version 4 supports addressing for read and write of up to
> 2*52 (4 petabytes) for native files.  This version is to be
> released "real soon now".  Preliminary development systems will
> be distributed at the APL2000 conference next week.

> If your problem is more urgent than that, I suggest you contact the
> helpline at (301)-564-5027

> /Mark Osborne


> > In APL+Win, version 3.6.09,  []nread is limited to reading from a
startbyte
> > less than 2*31 (~ 2.2 GB).  Does anyone know how to read a native file
from
> > a startbyte of greater than that limit?

> > Thanks, Joe.



Sat, 17 Apr 2004 05:15:40 GMT  
 APL+Win: how to read from native files greater than 2.2 GB?


Quote:
> APL+Win Version 4 supports addressing for read and write of up to
> 2*52 (4 petabytes) for native files.

Guess that will do for a couple of years...


Sat, 17 Apr 2004 07:45:13 GMT  
 APL+Win: how to read from native files greater than 2.2 GB?
I thought so too.

At a sustained data transfer rate of 10MB/sec (which I think
is a little high currently) it will take 13.6 years to fill
up that much space.  Of course the hardware, OS, and application
have to stay up that long, not to mention that current disk capacity
is still about 4 decimal orders of magnitude smaller than 2*52.

On the other hand I think they've progressed about 5 or 6
orders of magnitude over the last 15 or 20 years.

/Mark

Quote:



> > APL+Win Version 4 supports addressing for read and write of up to
> > 2*52 (4 petabytes) for native files.

> Guess that will do for a couple of years...



Mon, 19 Apr 2004 00:02:07 GMT  
 
 [ 8 post ] 

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