Eric,
Very close, the actual density is 6250BPI (bits per inch) so it would be

6250 x 12in x 2400ft = 180,000,000 or 175.78 MB ( a MB is 1,024,000
bytes).

We can use this calculation as bytes because the tape has 9 tracks 1 for
each bit plus parity.

But practically, I measured and found that on good tapes I consistently
got 140MB.

John Zoltak
North American Mfg Co

> -----Original Message-----
> From: Eric Bender [SMTP:[log in to unmask]]
> Sent: Thursday, August 13, 1998 2:56 PM
> To:   [log in to unmask]
> Subject:      Re: [HP3000-L] tape capacity
>
> At 11:18 AM 8/13/1998 -0700, Donna Garverick wrote:
> >i guess this is an oldie but a goodie sorta question...
> >
> >how much information can a 2400' reel (yes, reel) of tape
> >contain -- in theory.  i guess, perhaps, the better question
> >is -- does anyone remember the equation for calculating
> >this?       - d
> >
> >--
> >Donna Garverick     Sr. System Programmer
> >925-210-6631        [log in to unmask]
>
>
> So, assuming no Inter-Record (or Inter-Block) Gaps, at 1600 BPI that
> would be:
>
> 1600 x 12in/ft x 2400 = 46,080,000 bytes  (46 MB)
>
> and at 6400 BPI it'd be 184,320,000 bytes (184 MB).
>
> So, with IRG's and labels and other overhead, actual values would be
> less
> than these theoretical calculations.
>
> Regards, Eric Bender
>
> PS. Someone check these calculations. Please!