Here is a good page that discusses 64 bit issues http://en.wikipedia.org/wiki/64-bithttp://en.wikipedia.org/wiki/128-bit
2008/11/17 Matthew Brand <[EMAIL PROTECTED]> > Hi all, > > I originally asked this on general as part of a discussion about using > J64 on Linux under VMWare Fusion on a MacBook Pro, but it might be > better suited to the programming forum. > > In Ubuntu, System Monitor->Resources->Memory I have got 2.8 GB of free > memory indicated. Should I be able to create a 2GB mapped file inside > the 64 bit VAS? I.e. should the code below work? Also, does the amount > of free memory matter anyway? Can mapped files be larger than the > amount of physical memory? I thought that with J64 I would be able to > (if I had enough disk space and time) create a mapped variable of size > 2^64 bytes, is that untrue? > > Thanks, > Matthew. > > 2^30x > 1073741824 > size =. 1073741824 > bigfn =. jpath '~temp\big.jmf' > createjmf_jmf_ bigfn;size > map_jmf_ 'bigvar';bigfn NB. try to create a 1GB mapped > variable... succeeds > bigvar =: size # 'x' > unmap_jmf_ 'bigvar' > 0 > 2^31x > 2147483648 > size =. 2147483648 > bigfn =. jpath '~temp\big.jmf' > createjmf_jmf_ bigfn;size > map_jmf_ 'bigvar';bigfn NB. try to create a 2GB mapped variable... > fails > |bad jmf header: assert > | 'bad jmf header' assert 0[free fh,mh,fad > > This is the amount of free memory on the system: > [EMAIL PROTECTED]:~$ free -b -t > total used free shared buffers cached > Mem: 3727347712 874741760 2852605952 0 33710080 273428480 > -/+ buffers/cache: 567603200 3159744512 > Swap: 937639936 0 937639936 > Total: 4664987648 874741760 3790245888 > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > -- Björn Helgason, Verkfræðingur Fugl&Fiskur ehf, Þerneyjarsundi 23, Hraunborgum Po Box 127,801 Selfoss , t-póst: [EMAIL PROTECTED] gsm: +3546985532 Landslags og skrúðgarðagerð, gröfuþjónusta http://groups.google.com/group/J-Programming Tæknikunnátta höndlar hið flókna, sköpunargáfa er meistari einfaldleikans góður kennari getur stigið á tær án þess að glansinn fari af skónum /|_ .-----------------------------------. ,' .\ / | Með léttri lund verður | ,--' _,' | Dagurinn í dag | / / | Enn betri en gærdagurinn | ( -. | `-----------------------------------' | ) | (\_ _/) (`-. '--.) (='.'=) `. )----' (")_(")
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