Format:DSK disk image file format - Revision history

Phi2x: /* Extensions to the above specification */

2024-10-14T16:47:55Z

‎Extensions to the above specification

2024-10-14T15:47:52Z

‎Extensions to the above specification

2024-10-14T15:46:27Z

‎Extensions to the above specification

2024-10-14T15:37:48Z

‎Extensions to the above specification

2024-03-22T23:36:37Z

‎Extensions to the above specification

2024-02-15T09:01:26Z

‎Sector info

2022-10-21T17:34:45Z

Updated with more details on sector size to denote that its unit is 256-bytes.

2017-10-08T00:08:56Z

‎Disc Information block: Fixed typo

2010-12-17T19:19:59Z

2010-03-26T11:50:20Z

‎TRACK INFORMATION BLOCK

@@ Line 458: / Line 458: @@
 :3. How to determine the actual rate. The NEC765 floppy disc controller is supplied with a single clock. When reading from and writing to a disc using the NEC765 you can choose FM or MFM recording modes. Use of these modes and the clock into the NEC765 define the final rate at which the data is written to the disc.
 :When FM recording mode is used, data is read from or written to at a rate which is double that of when MFM is used. The time for each bit will be twice the time for MFM.
-:Also, the actual rate is twice longer that of the datasheet as the NEC765 clock is 4MHz on CPC instead of 8MHz for the datasheet.
+:Also, the actual rate is twice longer than indicated in the datasheet as the NEC765 clock runs at 4MHz on CPC instead of 8MHz for the datasheet.
 :Examples:

@@ Line 458: / Line 458: @@
 :3. How to determine the actual rate. The NEC765 floppy disc controller is supplied with a single clock. When reading from and writing to a disc using the NEC765 you can choose FM or MFM recording modes. Use of these modes and the clock into the NEC765 define the final rate at which the data is written to the disc.
 :When FM recording mode is used, data is read from or written to at a rate which is double that of when MFM is used. The time for each bit will be twice the time for MFM.
-:Also, the actual rate is twice that of the datasheet as the NEC765 clock is 4MHz on CPC instead of 8MHz for the datasheet.
+:Also, the actual rate is twice longer that of the datasheet as the NEC765 clock is 4MHz on CPC instead of 8MHz for the datasheet.
 :Examples:

@@ Line 457: / Line 457: @@
 :3. How to determine the actual rate. The NEC765 floppy disc controller is supplied with a single clock. When reading from and writing to a disc using the NEC765 you can choose FM or MFM recording modes. Use of these modes and the clock into the NEC765 define the final rate at which the data is written to the disc.
 :When FM recording mode is used, data is read from or written to at a rate which is double that of when MFM is used. The time for each bit will be twice the time for MFM.
 :Examples:
@@ Line 468: / Line 469: @@
 | 4MHz
 | FM
-| 4µs per bit
+| 8µs per bit
 |-
 | 4MHz
 | MFM
-| 2µs per bit
+| 4µs per bit
 |}

@@ Line 419: / Line 419: @@
 {| border="1"
 |-
-! Date rate
+! Data rate
 ! description
 |-
@@ Line 441: / Line 441: @@
 {| border="1"
 |-
-! Date rate
+! Mode
 ! description
 |-

@@ Line 466: / Line 466: @@
 ! Actual rate
 |-
-| 4Mhz
+| 4MHz
 | FM
-| 4us per bit
+| 4µs per bit
 |-
-| 4Mhz
+| 4MHz
 | MFM
-| 2us per bit
+| 2µs per bit
 |}

@@ Line 167: / Line 167: @@
 **b0 MA (Missing Address Mark)
 *The following bits are used from NEC765 status register 2:
-**b5 CM (Control Mark)
+**b6 CM (Control Mark)
 **b5 DD (Data Error in Data field)
 **b0 MD (Missing address Mark in Data field)

@@ Line 118: / Line 118: @@
 *"number of sectors" is used to identify the number of valid entries in the sector information list.
-*"sector size" parameter is used to calculate the location of each sector's data. Therefore, The data allocated for each sector must be the same. If the track contains different sized sectors, then the data allocated must be the size of the biggest sector. The "sector size" parameter is used to calculate the location of the sector data.
+*"sector size" parameter is used to calculate the location of each sector's data. Therefore, The data allocated for each sector must be the same. If the track contains different sized sectors, then the data allocated must be the size of the biggest sector. The "sector size" parameter is used to calculate the location of the sector data. Note that sector size's unit is 256-bytes. So, a sector size of 2, translates to 256 << (2-1), or 512 bytes.
 *Sector data always follows Track Information Block at offset &amp;100 from the start of the track information block.
 *Sector data is stored in the same order as the sectors in the sector info block.

@@ Line 11: / Line 11: @@
 == Disc Information block  ==
-The "Disc Information block" is always at offset 0 in the disk image file. If track data exists, then this will immediatly follow the Disc Information Block and will start at offset &amp;100 in the disc image file.
+The "Disc Information block" is always at offset 0 in the disk image file. If track data exists, then this will immediately follow the Disc Information Block and will start at offset &amp;100 in the disc image file.
 The "Disc Information block" has the following structure:

← Older revision		Revision as of 19:19, 17 December 2010
Line 1:		Line 1:
		+	[[Category:Cpctech.org]]
	<div style="border: 1px solid rgb(228, 222, 222); margin: 0px 0px 5px; padding: 0.5em 1em; background-color: rgb(249, 249, 249);">		<div style="border: 1px solid rgb(228, 222, 222); margin: 0px 0px 5px; padding: 0.5em 1em; background-color: rgb(249, 249, 249);">
	<center>		<center>

@@ Line 305: / Line 305: @@
 ! bytes
 |-
-| 00 - 0c
+| 00 - 0b
 | "Track-Info\r\n"
-| 13
+| 12
 |-
-| 0d - 0f
+| 0c - 0f
 | unused
-| 3
+| 4
 |-
 | 10