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Groups > comp.lang.python > #32313

Re: Fast forward-backward (write-read)

Date 2012-10-28 15:20 +0100
From Virgil Stokes <vs@it.uu.se>
Subject Re: Fast forward-backward (write-read)
References (3 earlier) <5086DA4D.4060204@tim.thechases.com> <mailman.2683.1351018926.27098.python-list@python.org> <7xr4ooah0t.fsf@ruckus.brouhaha.com> <50879555.7000200@it.uu.se> <508D1469.5060109@davea.name>
Newsgroups comp.lang.python
Message-ID <mailman.2971.1351434054.27098.python-list@python.org> (permalink)

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On 28-Oct-2012 12:18, Dave Angel wrote:
> On 10/24/2012 03:14 AM, Virgil Stokes wrote:
>> On 24-Oct-2012 01:46, Paul Rubin wrote:
>>> Virgil Stokes <vs@it.uu.se> writes:
>>>> Yes, I do wish to inverse the order,  but the "forward in time" file
>>>> will be in binary.
>>> I really think it will be simplest to just write the file in forward
>>> order, then use mmap to read it one record at a time.  It might be
>>> possible to squeeze out a little more performance with reordering tricks
>>> but that's the first thing to try.
>> Thanks Paul,
>> I am working on this approach now...
> If you're using mmap to map the whole file, you'll need 64bit Windows to
> start with.  I'd be interested to know if Windows will allow you to mmap
> 100gb at one stroke.  Have you tried it, or are you starting by figuring
> how to access the data from the mmap?
Thanks very much for pursuing my query, Dave.

I have not tried it yet --- temporarily side-tracked; but, I will post my 
findings on this issue.

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Thread

Re: Fast forward-backward (write-read) Virgil Stokes <vs@it.uu.se> - 2012-10-23 20:37 +0200
  Re: Fast forward-backward (write-read) Paul Rubin <no.email@nospam.invalid> - 2012-10-23 16:46 -0700
    Re: Fast forward-backward (write-read) Dave Angel <d@davea.name> - 2012-10-28 07:18 -0400
    Re: Fast forward-backward (write-read) Virgil Stokes <vs@it.uu.se> - 2012-10-28 15:20 +0100
    Re: Fast forward-backward (write-read) Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2012-10-28 18:21 +0000
    Re: Fast forward-backward (write-read) Virgil Stokes <vs@it.uu.se> - 2012-10-28 23:36 +0100

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