john@unisoft.UUCP (John Sovereign) (06/18/88)
A/UX inherits support for file size limits from System V, which provides a ulimit(2) system call that allows a process to query and set its file size limit (among other things). The ulimit(2) file size is defined in 512-byte blocks and may only be increased if you're root. The default limit in A/UX is equivalent to 8 GB, which exceeds the size which you may actually create since the file offset is an unsigned long (32-bits). Let me know if you ever create a 2 GB file. :-> John Sovereign UniSoft Corporation uunet!unisoft!john #include <disclaimer.h>
zdenko@csd4.milw.wisc.edu (Zdenko Tomasic) (06/18/88)
In article <1190@unisoft.UUCP> john@unisoft.UUCP (John Sovereign) writes: > >A/UX inherits support for file size limits from System V, >which provides a ulimit(2) system call that allows a process >to query and set its file size limit (among other things). >The ulimit(2) file size is defined in 512-byte blocks and >may only be increased if you're root. > >The default limit in A/UX is equivalent to 8 GB, which exceeds >the size which you may actually create since the file offset is >an unsigned long (32-bits). > Thanks for the info! >Let me know if you ever create a 2 GB file. :-> ^^^^ > Let's see: In quantum chemistry calculations, in order to calculate electronic energy (including electron correlation) of a substance, one needs roughly N**4/8 integrals. N is a size of a basis functions used in integral calculation. If one sticks to not-so-big 4-31G basis set which includes 2 functions for hydrogen (H) and 9 for carbon (C), oxygen (O) and nitrogen (N) each, the ordinary CHOLESTEROL molecule (C27H46O) will require N of 344 (=27*9+46*2+9) basis functions. In that case there are 1 750 426 112 integrals which in double precision (with 8 bytes per integral) means a file of 14 003 408 896 bytes, i.e. more than 14 GB. ^^^^^ Of course, one would not try that on Mac, but maybe (or maybe not even there!) Cray or ETA-10 . You see, such big files are not all that unusual, not to mention real big bio-molecules (hundreds, thousands of atoms). They are naturally out of reach for serious calculations with present resources. >John Sovereign >UniSoft Corporation >uunet!unisoft!john >#include <disclaimer.h> Zdenko Tomasic UWM, Chem. Dept. Milwaukee,WI,53201 __________________________________________________________ UUCP: ihnp4!uwmcsd1!uwmcsd4!zdenko ARPA: zdenko@csd4.milw.wisc.edu __________________________________________________________
phil@Apple.COM (Phil Ronzone) (06/21/88)
In article <6034@uwmcsd1.UUCP> zdenko@csd4.milw.wisc.edu (Zdenko Tomasic) writes: >>Let me know if you ever create a 2 GB file. :-> >Let's see: >In quantum chemistry calculations, in order to calculate electronic >energy (including electron correlation) of a substance, one needs >roughly N**4/8 integrals ... means a file of 14 003 408 896 bytes, >i.e. more than 14 GB. Well, shucks. That's almost as big as my database file that will contain the coordinates (relative to the center of the universe) of every atom in the universe as well as misc. info as velocity, energy states and history. So far, it looks like it will take more than a few CD ROMs. ---------------------------------------------------------------- -- Philip K. Ronzone A/UX System Architect Apple Computer MS 27AJ 10500 N. DeAnza Blvd. Cupertino CA 95014 {amdahl,decwrl,sun,voder,nsc,mtxinu,dual,unisoft}!apple!phil "In A/UX Release 4.0, /bin will still be there ...." P. Zigbooli