Datasheet

Inquiry Metadata Storage (subcommand code - 02h) enables host to read capacity of the Metadata
Storage of the device along with information associated with the charasteristics of the Metadata Storage.
The data returned from the device is in following format.
reserved0000h7 - 255
number of sectors per device(high)xxxxh6
number of sectors per device(low)xxxxh5
metadata capacity in bytes (high)0000h4
metadata capacity in bytes (low)0020h3
media status wor
d
bit 0: 1 = content changed
0 = content not changed
bit 1-15: reserved
000xh2
media property
bit 0: 1 = rotating, 0 = silicon
bit 1-15: reserved
0000h1
data format revision0001h0
Descriptiondataword
Figure 72. Data format of Inquiry Metadata Storage
Reserved bits and words are 0. Bit 0 of media status word (word 2) indicates whether the main storage
contents have been changed by any commands (such as Write Sectors, Format Track, or Erase
Sectors). Media status word is also returned by Read Metadata Storage as a header part of metadata.
Read Metadata Storage enables the host to read from device's metadata storage. Cylinder Low and
Cylinder High Registers are used to specify the metadata block address, which can range from
0 to ([metadata capacity in bytes + 2] / 512). Sector Count Register is used to specify the number of
sectors to transfer. For the microdrive, Cylinder Low and Cylinder High Registers must be 00h, Sector
Count Register must be 01h because of the total capacity of metadata storage (32 bytes). The first block
of metadata contains media status word that is also returned by Inquiry Metadata Media. Both words re-
present the identical information.
Reserved0000h
33-25
5
metadata (32 bytes)xxxxh1-32
media status wor
d
bit 0: 1 = content changed
0 = content not changed
bit 1-15: reserved
000xh0
Descriptiondataword
Figure 73. Data format of Read Metadata Storage
Reserved words would be used if the device has more than 32 bytes of metadata capacity. The host
should not assume capacity of metadata to be 32 bytes. The number is merely IBM Microdrive's imple-
mentation.
Write Metadata enables the host to write to the metadata storage of the device. Usage of Cylinder Low,
Cylinder High and Sector Count Registers are the same as Read Metadata. Upon successful completion
of Write Metadata, media status is reset to "unchanged" condition and subsequent media status word (by
either Inquiry Metadata Media or Read Metadata) will show bit 0 cleared until the device receives any
commands that changes the main storage contents.
Hard disk drive specification for DSCM-11000/-10512/-10340
86