> On Sep 7, 2016, at 2:45 PM, Al Kossow <a...@bitsavers.org> wrote: > > > > On 9/7/16 11:21 AM, Paul Koning wrote: > >> That would fit the IBM 2315 if indeed it used one sector notch for each >> sector (it has 8 per track). >> > > and 100 TPI > > Original Diablo drives were also 100 TPI, and used silver colored heads, > moving to 200 TPI and the more > common white ceramic heads. > > Apparently, the 100 TPI Diablo heads are extremely difficult to find today. I > remember all the 100 TPI > Diablo drives at a friend's company getting converted to 200.
TPI, as in "transitions per inch"? I vaguely remember that the 1311 (20 sectors of 200 digits each per track) used silvery colored heads. I wonder if those are the same. They were pretty sturdy; one day when we had a hydraulic leak, the FE just cleaned heads and pack with isopropyl alcohol, fixed the leak, and put the drive and pack back into service. paul