Skip to content

m525hd.md

Latest commit

 

History

History
95 lines (83 loc) · 4.4 KB

m525hd.md

File metadata and controls

95 lines (83 loc) · 4.4 KB

Mackapar Media m525hd

                                      .!.
                                     !!!!!.
                                  .   '!!!!!.
                                .!!!.   '!!!!!.
                              .!!!!!!!.   '!!!!!.
                            .!!!!!!!!!'   .!!!!!!!.
                            '!!!!!!!'   .!!!!!!!!!'
                              '!!!!!.   '!!!!!!!'
                                '!!!!!.   '!!!'
                                  '!!!!!.   '
                                    '!!!!!
                                      '!'


                          M A C K A P A R    M E D I A
Item Value Comment
Vendor code 0x1eb37e91 Mackapar Media
Device ID 0x4ac5525d 5.25" Hard Disk Drive
Device type 0x4ac5 16 bit fixed Disk Drive
Version 0x0001 Dictates Size (5MB, 10MB)

Device Description

Mackapar Medias first foray into fixed storage resulted in the Mackapar Media m525hd. When formatted in 16 bit mode the m525hd has a capacity of 5MB. Data is saved on 4 surfaces each containing 64 20-sector tracks. Each sector contains a total of 512 words, resulting in a total of 5120 sectors. Reads and writes are performed asynchronously, at a read/write speed of 327.7kw/s and a Track-to-Track seek time of around 3ms. The average seek time is 80ms with a maximum of 200ms (200 cycles).

Interrupt Commands

  • 0x0000: POLL_DEVICE
    • Sets B to the current state (see below) and C to the latest error since the last device poll
  • 0x0001: SET_INTERRUPT
    • Enables interrupts and sets the message to X if X is anything other than 0, disables interrupts if X is 0. When interrupts are enabled the m525hd will trigger an interrupt on the DCPU-16 whenever the state or error message changes
  • 0x0002: READ_SECTOR
    • Reads sector X to DCPU ram starting at Y. Sets B to 1 if reading is possible and has been started, anything else if reading fails. Reading is only possible if the state is STATE_READY or STATE_READY_WP. Protects against partial reads.
  • 0x0003: WRITE_SECTOR
    • Writes sector X from DCPU ram starting at Y. Sets B to 1 if writing is possible and has been started, anything else if writing fails. Writing is only possible if the state is STATE_READY. Protects against partial writes.
  • 0x0004: SPIN_DOWN
    • Parks the heads and spins down the drive to conserve power.
  • 0x0005: SPIN_UP
    • Spins up the drive to make ready for reading/writing. The drive will need a 15 second interval to reach the proper speed.

State Codes

Value Code Description
0x0001 STATE_READY The drive is ready to accept commands.
0x0002 STATE_READY_WP The drive is ready but read only.
0x0003 STATE_BUSY The drive is busy either reading, writing or seeking.
0x0004 STATE_PARKED The drive has been spun down and needs to be restarted.
0x0005 STATE_PARKED_WP The drive has been spun down and is write protected.
0x0006 STATE_INIT The drive is still spinning up.
0x0007 STATE_INIT_WP The drive is still spinning up and is write protected.
Error Codes
Value Code Description
0x0000 ERROR_NONE There has been no error since the last poll.
0x0001 ERROR_BUSY The drive is busy performing an action.
0x0002 ERROR_BAD_ADDRESS Attempted to read from a sector this drive doesn't contain
0x0003 ERROR_PROTECTED Tried to write to read only drive.
0x0004 ERROR_PARKED Attempted to read/write from a spun down drive.
0x0005 ERROR_BAD_SECTOR The requested sector is broken, the data on it is lost.
0xFFFF ERROR_BROKEN Theres been some major software or hardware problem.

Behaviours

When first powered on (or after being spun down) the m525hd requires a 15 second interval in which to spin up. Attempting to access the drive during this time should return a state code of STATE_INIT(_WP) and an Error Code of ERROR_BUSY. At the end of these 15 seconds the drive should report STATE_READY(_WP).

Maximum seek time is observed when seeking from track 0,1,2,3 (rest) to track 252,253,254,255 (center of drive). Minimum seek time is observed when seeking between adjacent tracks.