[TUHS] Unix V6 on SimH

Carl Lowenstein carl.lowenstein at gmail.com
Sun Apr 25 07:19:57 AEST 2010

On Sat, Apr 24, 2010 at 9:16 AM, Andrew Sealy-Bell
<andyamsterdam2003 at gmail.com> wrote:
> Hi, doesn't anybody know if there is a disk size limit on Unix 6? I wrote a
> C program to create a file and it won't go above around 1.5Mb.  It doesn't
> crash or report any errors but the file size never exceeds around that size.
>  Maybe it's a disk size limitation?

According to my memory, reinforced by reading the manual section File
System (V), there are several limits.

The disk size (in 512-byte blocks) is kept in the super-block as a
16-bit integer.  This implies at most a 32MB file system.  Since at
that time there was only one file system per disk, that means a
maximum 32MB disk.

The file size (in bytes) is kept in an i-node as a 24-bit number,
implying a maximum 16MB file.

    carl lowenstein         marine physical lab     u.c. san diego
                                                 clowenstein at ucsd.edu

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