[Info-vax] VSI roadmap

[David Jones]

On Wednesday, August 23, 2023 at 4:24:17 PM UTC-4, Arne Vajhøj wrote:
> On 8/23/2023 8:47 AM, David Jones wrote: 
> > I'm not sure that's true, given how slow hardware was 45 years ago. Adding 
> > 6 bytes of meta-data to a VAR file with an average record length of 30 
> > characters will increase the size by 18%. More space on disk and more I/O 
> > operations to process the file.
> I am not sure that I can follow the math. 
> 
> Current VAR record overhead is header 2 bytes + average 0.5 even 
> pad byte and 2.5/30 is 8.3%. 
> 
> Increasing to 32 bit would mean header 4 bytes + average 0.5 even 
> pad byte and 4.5/30 is 15.0%. 
>
> Increasing to 32 bit and add trailer length to support reading 
> backwards would mean header 4 bytes + average 0.5 even pad byte 
> + trailer 4 bytes and 8.5/30 is 28.3%. 
>

I was comparing data+overhead in the 8 byte case and 2 byte case:
128.3% / 108.3% = 118.46%
 
> Yes - it is some overhead. But NOS/VE is almost as old as 
> VMS and used header 6 bytes and trailer 6 bytes. They could 
> apparently live with it. 

NOS/VE  is a 64-bit OS for CDC mainframes, quite a different animal than the
 VAX/VMS environment.