GeneveOS Device Operation - Revision history

Mizapf: /* BWRITE */

2022-04-24T19:43:05Z

BWRITE

← Older revision		Revision as of 19:43, 24 April 2022
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	\| -		\| -
	\| colspan="3" \| Buffer address		\| colspan="3" \| Buffer address
	\| colspan="2" \| Sector offset		\| colspan="2" \| Sector offset LSW
	\| colspan="2" \| -		\| colspan="2" \| -
			\| CPU / VDP
	\| -		\| -
	\| colspan="3" \| Number of sectors		\| colspan="2" \| Number of sectors
	\| -		\| Sector offset MSB
	\| Name length		\| Name length
	\| Name		\| Name
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	\| Error code		\| Error code
	\| colspan="3" \| Updated buffer address		\| colspan="3" \| Updated buffer address
	\| colspan="2" \| ~~Next unwritten~~ sector		\| colspan="2" \| Updated sector offset LSW
	\| colspan="2" \| -		\| colspan="2" \| -
	\| -		\| -
	~~\| 0~~
	~~\| colspan="2" \| Number of unwritten sectors~~
	\| -		\| -
	\| ~~Name length~~		\| colspan="2" \| Remaining sectors
	\| ~~Name~~		\| Updated sector offset MSB
			\| -
			\| -
	\|-		\|-
	\|}		\|}
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	The '''Updated buffer address''' points to the memory address after the sectors were written (e.g. when 4 sectors are written, the pointer is increased by 4*256 = 1024).		The '''Updated buffer address''' points to the memory address after the sectors were written (e.g. when 4 sectors are written, the pointer is increased by 4*256 = 1024).

	The '''~~Next unwritten~~ sector''' is the first sector that has not been written due to an error condition.		The '''Updates sector offset''' is the first sector that has not been written due to an error condition.

	The '''~~Number of unwritten~~ sectors''' is the number of unwritten sectors due to an error condition.		The '''Remaining sectors''' is the number of unwritten sectors due to an error condition.

	<div class="warn">Unless you want to write directly to the device, make sure that the PAB contains a file name that points to a file, not to a device. For example, when the file name has been created by the program, and for some reason the file name is empty (like "HDS1."), the following write operation will overwrite the volume information block and the allocation tables and '''destroy the target device filesystem'''.</div>		<div class="warn">Unless you want to write directly to the device, make sure that the PAB contains a file name that points to a file, not to a device. For example, when the file name has been created by the program, and for some reason the file name is empty (like "HDS1."), the following write operation will overwrite the volume information block and the allocation tables and '''destroy the target device filesystem'''.</div>

Mizapf: /* BREAD */

2022-04-24T18:42:10Z

BREAD

← Older revision		Revision as of 18:42, 24 April 2022
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	The sector offset is defined by byte 0E as the most significant byte (value*65536) plus the word in bytes 06 and 07.		The sector offset is defined by byte 0E as the most significant byte (value*65536) plus the word in bytes 06 and 07.

	Byte 0A specifies whether the buffer address belongs to the CPU (0) or the VDP (non-zero) address space.		Byte 0A specifies whether the buffer address belongs to the CPU (0) or the VDP (non-zero) address space.

			* CPU buffer address: ...p pppp.pppx xxxx.xxxx xxxx. The first three bits are ignored; the next 8 bits specify the page number in the user task, and the remaining 13 bits provide the offset in the page.
			* VDP buffer address: .... ...x.xxxx xxxx.xxxx xxxx. The last 17 bits indicate the 128K video address.

	'''Read from file''': When a file is addressed, the operation reads a sequence of sectors from the file. The '''Sector offset''' is the number of the first sector of the file, counting from 0. The physical locations of the sectors are subject to the sector allocation on the device.		'''Read from file''': When a file is addressed, the operation reads a sequence of sectors from the file. The '''Sector offset''' is the number of the first sector of the file, counting from 0. The physical locations of the sectors are subject to the sector allocation on the device.

Mizapf: /* BREAD */

2022-04-24T18:30:57Z

BREAD

← Older revision		Revision as of 18:30, 24 April 2022
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	\|-		\|-
	\|}		\|}

			'''Error codes'''

			* '''60''': Bad operation; happens when the device is not a block device.
			* '''A0''': Read beyond end of file or device.
			* '''C0''': Media error. The system was unable to read the sector although it should be readable.
			* '''E0''': General error; happens when the device does not contain the specified file.

	The '''Updated buffer address''' points to the memory address after the sectors were read (e.g. when 4 sectors are read, the pointer is increased by 4*256 = 1024).		The '''Updated buffer address''' points to the memory address after the sectors were read (e.g. when 4 sectors are read, the pointer is increased by 4*256 = 1024).

Mizapf: /* BREAD */

2022-04-24T18:25:00Z

BREAD

← Older revision		Revision as of 18:25, 24 April 2022
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	\| colspan="2" \| Sector offset LSW		\| colspan="2" \| Sector offset LSW
	\| colspan="2" \| -		\| colspan="2" \| -
	\| CPU/VDP		\| CPU / VDP
	\| -		\| -
	\| colspan="2" \| Number of sectors		\| colspan="2" \| Number of sectors
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	\|}		\|}

	The '''Updated buffer address''' points to the memory address after the sectors were ~~written~~ (e.g. when 4 sectors are ~~written~~, the pointer is increased by 4*256 = 1024).		The '''Updated buffer address''' points to the memory address after the sectors were read (e.g. when 4 sectors are read, the pointer is increased by 4*256 = 1024).

	The '''~~Next unwritten~~ sector''' is the first sector that has not been ~~written~~ due to an error condition.		The '''Updated sector offset''' is the first sector that has not been read due to an error condition.

	The '''~~Number of unwritten~~ sectors''' is the number of ~~unwritten~~ sectors due to an error condition.		The '''Remaining sectors''' is the number of unread sectors due to an error condition.

	=== BWRITE ===		=== BWRITE ===

Mizapf: /* BREAD */

2022-04-24T18:01:59Z

BREAD

← Older revision		Revision as of 18:01, 24 April 2022
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	\| -		\| -
	\| colspan="3" \| Buffer address		\| colspan="3" \| Buffer address
	\| colspan="2" \| Sector offset		\| colspan="2" \| Sector offset LSW
	\| colspan="2" \| -		\| colspan="2" \| -
			\| CPU/VDP
	\| -		\| -
	\| colspan="3" \| Number of sectors		\| colspan="2" \| Number of sectors
	\| -		\| Sector offset MSB
	\| Name length		\| Name length
	\| Name		\| Name
	\|-		\|-
	\|}		\|}

			The sector offset is defined by byte 0E as the most significant byte (value*65536) plus the word in bytes 06 and 07.

			Byte 0A specifies whether the buffer address belongs to the CPU (0) or the VDP (non-zero) address space.

	'''Read from file''': When a file is addressed, the operation reads a sequence of sectors from the file. The '''Sector offset''' is the number of the first sector of the file, counting from 0. The physical locations of the sectors are subject to the sector allocation on the device.		'''Read from file''': When a file is addressed, the operation reads a sequence of sectors from the file. The '''Sector offset''' is the number of the first sector of the file, counting from 0. The physical locations of the sectors are subject to the sector allocation on the device.
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	\| Error code		\| Error code
	\| colspan="3" \| Updated buffer address		\| colspan="3" \| Updated buffer address
	\| colspan="2" \| ~~Next unwritten~~ sector		\| colspan="2" \| Updated sector offset LSW
	\| colspan="2" \| -		\| colspan="2" \| -
	\| -		\| -
	~~\| 0~~
	~~\| colspan="2" \| Number of unwritten sectors~~
	\| -		\| -
	\| ~~Name length~~		\| colspan="2" \| Remaining sectors
	\| ~~Name~~		\| Updated sector offset MSB
			\| -
			\| -
	\|-		\|-
	\|}		\|}

Mizapf: /* BREAD */

2022-04-24T17:42:08Z

BREAD

← Older revision		Revision as of 17:42, 24 April 2022
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	! width="4%" \| 10 ...		! width="4%" \| 10 ...
	\|-		\|-
	\| '''0B'''		\| '''0A'''
	\| -		\| -
	\| -		\| -
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	The '''Number of unwritten sectors''' is the number of unwritten sectors due to an error condition.		The '''Number of unwritten sectors''' is the number of unwritten sectors due to an error condition.

	<div class="warn">Unless you want to write directly to the device, make sure that the PAB contains a file name that points to a file, not to a device. For example, when the file name has been created by the program, and for some reason the file name is empty (like "HDS1."), the following write operation will overwrite the volume information block and the allocation tables and '''destroy the target device filesystem'''.</div>

	~~Tick here: [ ] Yes, I fully understood the danger of this operation.~~

	~~(The author lost a complete hard disk by this incident, and was lucky to have a backup.)~~

	~~<div style="margin-bottom:6em"></div>~~

	=== BWRITE ===		=== BWRITE ===

Mizapf: /* BREAD */

2022-04-24T17:40:35Z

BREAD

← Older revision		Revision as of 17:40, 24 April 2022
Line 526:		Line 526:

	=== BREAD ===		=== BREAD ===

			Reads a sector from a file or from a device. This is a level-2 operation, that is, it accesses the device based on sector addressing (or sectors of a file). BREAD allows for two operations:

			* Read sectors from a file.
			* Read sectors from a device.

			'''IN'''

			{\| class="plainc" style="margin-left:1%"
			\|-
			! width="4%" \| 00
			! width="4%" \| 01
			! width="4%" \| 02
			! width="4%" \| 03
			! width="4%" \| 04
			! width="4%" \| 05
			! width="4%" \| 06
			! width="4%" \| 07
			! width="4%" \| 08
			! width="4%" \| 09
			! width="4%" \| 0A
			! width="4%" \| 0B
			! width="4%" \| 0C
			! width="4%" \| 0D
			! width="4%" \| 0E
			! width="4%" \| 0F
			! width="4%" \| 10 ...
			\|-
			\| '''0B'''
			\| -
			\| -
			\| colspan="3" \| Buffer address
			\| colspan="2" \| Sector offset
			\| colspan="2" \| -
			\| -
			\| colspan="3" \| Number of sectors
			\| -
			\| Name length
			\| Name
			\|-
			\|}

			'''Read from file''': When a file is addressed, the operation reads a sequence of sectors from the file. The '''Sector offset''' is the number of the first sector of the file, counting from 0. The physical locations of the sectors are subject to the sector allocation on the device.

			'''Read from device''': When a device is addressed, the operation reads a sequence of sectors from the device. The '''Sector offset''' is the physical sector number.

			After the BREAD operation has completed, the PAB delivers information about the result:

			'''OUT'''

			{\| class="plainc" style="margin-left:1%"
			\|-
			! width="4%" \| 00
			! width="4%" \| 01
			! width="4%" \| 02
			! width="4%" \| 03
			! width="4%" \| 04
			! width="4%" \| 05
			! width="4%" \| 06
			! width="4%" \| 07
			! width="4%" \| 08
			! width="4%" \| 09
			! width="4%" \| 0A
			! width="4%" \| 0B
			! width="4%" \| 0C
			! width="4%" \| 0D
			! width="4%" \| 0E
			! width="4%" \| 0F
			! width="4%" \| 10 ...
			\|-
			\| -
			\| -
			\| Error code
			\| colspan="3" \| Updated buffer address
			\| colspan="2" \| Next unwritten sector
			\| colspan="2" \| -
			\| -
			\| 0
			\| colspan="2" \| Number of unwritten sectors
			\| -
			\| Name length
			\| Name
			\|-
			\|}

			The '''Updated buffer address''' points to the memory address after the sectors were written (e.g. when 4 sectors are written, the pointer is increased by 4*256 = 1024).

			The '''Next unwritten sector''' is the first sector that has not been written due to an error condition.

			The '''Number of unwritten sectors''' is the number of unwritten sectors due to an error condition.

			<div class="warn">Unless you want to write directly to the device, make sure that the PAB contains a file name that points to a file, not to a device. For example, when the file name has been created by the program, and for some reason the file name is empty (like "HDS1."), the following write operation will overwrite the volume information block and the allocation tables and '''destroy the target device filesystem'''.</div>

			Tick here: [ ] Yes, I fully understood the danger of this operation.

			(The author lost a complete hard disk by this incident, and was lucky to have a backup.)

	<div style="margin-bottom:6em"></div>		<div style="margin-bottom:6em"></div>

Mizapf at 10:56, 23 July 2016

2016-07-23T10:56:16Z

Show changes

Mizapf at 21:04, 22 July 2016

2016-07-22T21:04:29Z

@@ Line 74: / Line 74: @@
 After the operation, the PAB contains information about the results of the operation.
-'''Error code'''
+=== Mode ===
 The error code is an eight bit word with the following structure:

Mizapf at 20:40, 22 July 2016

2016-07-22T20:40:04Z

← Older revision		Revision as of 20:40, 22 July 2016
Line 73:		Line 73:

	After the operation, the PAB contains information about the results of the operation.		After the operation, the PAB contains information about the results of the operation.

			'''Error code'''

			The error code is an eight bit word with the following structure:

			{\| class="plainbits" style="float:left"
			! 0
			! 1
			! 2
			! 3
			! 4
			! 5
			! 6
			! 7
			\|-
			\| colspan="3" \| Number
			\| colspan="5" \| Detail code for error 7
			\|}

			{\| class="plainc" style="float:left"
			! Number
			! Meaning
			\|-
			\| 0
			\| No such device
			\|-
			\| 1
			\| Write-protected
			\|-
			\| 2
			\| Illegal open attribute
			\|-
			\| 3
			\| Illegal operation
			\|-
			\| 4
			\| Out of buffer space
			\|-
			\| 5
			\| Read beyond EOF
			\|-
			\| 6
			\| Device error
			\|-
			\| 7
			\| File error
			\|}

			<div style="clear:both"></div>

	== Operations ==		== Operations ==