Media - HP Vectra Reference Manual

One of the read/write channels is optimized to transfer data to
and from the media at 500kHz, the other channel is optimized to
transfer data to and from the media at 300kHz. The 500kHz
channel is designed to be used with HP92190X High-Capacity 96
tpi Discs. HP92190X is a high coercivity (approximately 650
Oersteds) media. When this drive is used with HP921 90X media,
1.2MB of formatted data can be stored and read.
The 300kHz channel is designed to be used with HP921 90A
Double-Sided Double-Density Discs. Because the bit storage
density of the HP921 90A disc is not as high as HP921 90X discs,
when this media is used in the 1.2MB drive, the flexible disc
controller enables the 300kHz channel and issues double STEP
pulses to the drive. (Refer to Section 2 for detailed information on
the flexible disc controller subsystem.) As a result, the 1.2MB
Internal Flexible Disc Drive can format and write a Double-Sided
Double-Density Disc in a similar way as the 360KB Internal Flexible
Disc Drive. However, since the read/write gap is half as wide as
the gap in the 360KB Internal Flexible Disc Drive head, the 360KB
Internal Flexible Disc Drive and other similar drives cannot read the
signal on these smaller tracks.
Media
Note the following when using the 1.2MB Internal Flexible Disc
Drive:
• Use of HP921 90X High-Capacity Discs will result in maximum
storage capacity.
• HP92190X High-Capacity Discs are designed to be used only
with the 1.2MB Internal Flexible Disc Drive. They will not work
in the 360KB Internal Flexible Disc Drive.
*
• The 1.2MB Internal Flexible Disc Drive can read and write data
with HP92190A Double-Sided Discs. After being used in the
1.2 drive, the discs will not be able to be read or written on
the 360KB Internal Flexible Disc Drive because of the
narrower track.
**
106 Disc Drives