BACKUP-SYSTEM - Revision history

Tingo: change link to ND-210337 so it works

2020-05-20T20:35:50Z

change link to ND-210337 so it works

← Older revision		Revision as of 20:35, 20 May 2020
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	The '''BACKUP SYSTEM''' is a subsystem used for copying files from one storage medium to another. BACKUP means making an extra copy of a disk pack or individual files which can be kept in a safe place. If the need arises, this copy can be used later for recovery of deleted files or corrupted data. This manual		The '''BACKUP SYSTEM''' is a subsystem used for copying files from one storage medium to another. BACKUP means making an extra copy of a disk pack or individual files which can be kept in a safe place. If the need arises, this copy can be used later for recovery of deleted files or corrupted data. This manual
	describes: BACKUP-SYSTEM [[ND-~~210337H~~\|ND 210337H]], the stand-alone programs for taking backup, and the [[SINTRAN III]] commands for taking backup<ref>{{ND-doc\|60.250.1 EN}}</ref>.		describes: BACKUP-SYSTEM [[:Category:ND-210337\|ND 210337H]], the stand-alone programs for taking backup, and the [[SINTRAN III]] commands for taking backup<ref>{{ND-doc\|60.250.1 EN}}</ref>.

Tingo: /* Label format on magnetic tape volumes */ special rules for disk and streamer

2020-05-19T08:53:20Z

Label format on magnetic tape volumes: special rules for disk and streamer

← Older revision		Revision as of 08:53, 19 May 2020
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	- A HOLE label is written as a deleted record to distinguish it from data, and the EOF mark preceding the EOF1-1abel is written as a deleted record containing the identifier 'EOF*' in the first 4 bytes of the record, to distinguish if from a HOLE label.		- A HOLE label is written as a deleted record to distinguish it from data, and the EOF mark preceding the EOF1-1abel is written as a deleted record containing the identifier 'EOF*' in the first 4 bytes of the record, to distinguish if from a HOLE label.

			=== Special rules for disk and streamer ===
			A11 the labels in front of, between, or at the end of files on disk or streamer volumes are written in one sector, and they have fixed positions in the sector. An exception from this may be the case where one needs several UHLn labels (n>1) to contain a logical bit file (based on the index blocks) of large indexed files, when normal file backup on disk or streamer volumes is implemented.


			BEGINNING OF VOLUME.

			VOL1 Zero-word Zero-word HDR1 HDR2 UHL1 EOF-word

			The Zero-word contains only 0, while the EOF-word contains binary 3 (EOF) in the first byte, and an asterisk (*) in the last byte.


			BETWEEN FILES.

			Eof-word EOF1 Eof-word HDR1 HDR2 UHL1 Eof-word


			END OF VOLUME.

			EOF1
			Eof-word < or > Eof-word Eof-word
			EOV1

			if the volume is not empty. If the volume is empty, the contents of the first sector is:

			VOL1 Zero-word Eof-word Eof-word

			The labels and Zero/Eof-words in front of, or between files will thus take 4 * 80 bytes + 3 * 2 bytes = 326 bytes = 163 words of a sector.

	== Product number ==		== Product number ==

Tingo: /* Label format on magnetic tape volumes */ special rules for floppy volumes

2020-05-19T08:45:27Z

Label format on magnetic tape volumes: special rules for floppy volumes

← Older revision		Revision as of 08:45, 19 May 2020
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	57-60 Max. byte pointer = number of pages * 2048 - 1		57-60 Max. byte pointer = number of pages * 2048 - 1
	61-64 File pointer. Start page of source device on disk		61-64 File pointer. Start page of source device on disk

			=== Special rules for floppy volumes ===
			- Only floppy formats 0 and 17 are allowed.

			- Each label group (HDR1 HDR2 UHL1) is written in one record (sector on the floppy).

			- A HOLE label is written as a deleted record to distinguish it from data, and the EOF mark preceding the EOF1-1abel is written as a deleted record containing the identifier 'EOF*' in the first 4 bytes of the record, to distinguish if from a HOLE label.

	== Product number ==		== Product number ==

Tingo: /* Modifications for device backup */ describe headers

2020-05-19T08:42:23Z

Modifications for device backup: describe headers

← Older revision		Revision as of 08:42, 19 May 2020
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	The ANSI labels of a destination volume are then generated as follows:		The ANSI labels of a destination volume are then generated as follows:

			==== VOL1 - Volume header label ====
			FIELD 3 - Volume serial number {volume name).

			Each time a device is copied to a volume, a new volume is automatically created by the system. The volume name is not
			explicitely given by the user, but decided by the system to be BACKUP.

			FIELD 7 - Owner identification (name of owner).

			The owner will be SYSTEM.

			==== HDR1 - First file header label ====
			FIELD 3 - File identifier (file name).

			The file name is the name of the source device, for example
			DISC-75MB-1

			FIELD 4 - Set identification (file type).

			The file type is the unit/subunit identification given as, for instance, 1 (unit 1) if there are no subunits, or 1-2
			if subunit 2 is copied, or 2R or 2F1 if the source is a Phoenix disk with removable (R) and fixed (F) subunits (2F1 means fixed subunit 1 of unit 2).

			FIELDS 6, 7 and 8 - Sequence, generation and version numbers. Since a new volume is created each time a device
			is copied, the copy will be the first file on the volume, and thus the sequence number is 0001. When the DEVICE-COPY
			function is COPY, the generation and version numbers are set to 1.

			==== HDR2 - Second file header label ====
			FIELD 6 - Res. for operating systems (length: 35 bytes).

			- Bytes 1 - 16:
			ND-CPU-xxxxxxxxx where xxx... is the CPU number of the system, left-justified and terminated by an apostrophe.
			This may be regarded as the owner of the file.

			- Bytes 17 - 32:
			Directory name of the source.

			- Byte 33:
			Directory index of the source.

			- Bytes 34 - 35:
			File system flag word (DFLAG) of the directory table entry of the source.

			==== UHL1 - User label ====
			FIELD 3 - User option (length: 76 bytes)
			- Bytes 1 - 2:
			Binary generation (= version) number.

			- Bytes 3 - 4:
			Total number of generations.

			- Bytes 5 - 8:
			Copy date in the standard SINTRAN III file system format.

			- Bytes 9 - 12:
			Start page number. When the section number of the HDR1
			label is > 1 (the device copy is split into several vol-
			umes), this is the start page of the current section. If
			the section number is 1, and the start page is >< to the
			file pointer of the device object entry (see below), then
			the source device was a main directory containing
			SINTRAN III, and:

			start page - file pointer =
			logical number of first page behind (SYSTEM)SEGFILO:DATA

			Thus, when recovering this file, one may skip SINTRAN III.

			- Bytes 13 - 76:
			Device object entry (length: 64 bytes). This object entry
			is constructed by the backup system, and is quite similar
			to an ordinary SINTRAN III file system object entry. It
			describes the source device, and contains the following:

			===== Device object entry in field 3 =====
			POSITION CONTENTS
			IN OBJECT
			ENTRY

			1- 2 Flag word (NFLAG) of the name table entry of the device
			3-18 Device name
			19-22 Unit subunit: 1', 2-1', 1R', 2F1' (see HDR1 file type)
			23-26 Zero (version chain pointers)
			27-28 Access word is 1, i.e. only owner read access
			29-30 File attribute word is 20B, i.e. contiguous file
			31-32 Unit and device number (DUNIT) from the directory entry
			33-34 Term.no. and user index of the user who made the copy
			35-36 Subunit and name index (LUNIT) from the directory entry
			37-52 Zero (open counts and dates)
			53-56 Number of pages in file (source device)
			57-60 Max. byte pointer = number of pages * 2048 - 1
			61-64 File pointer. Start page of source device on disk

	== Product number ==		== Product number ==

Tingo: /* Label format on magnetic tape volumes */ modifications for device backup

2020-05-19T08:23:23Z

Label format on magnetic tape volumes: modifications for device backup

← Older revision		Revision as of 08:23, 19 May 2020
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	73-76 77-80 (32-bit binary number stating the logical		73-76 77-80 (32-bit binary number stating the logical
	block number of the following data block)		block number of the following data block)

			=== Modifications for device backup ===
			When a complete device unit is copied to a volume on disk or tape, the copy of the device unit/subunit on the volume
			is a normal volume file. If the backup system command DEVICE-COPY is used, the system itself decides whether a
			device should contain a volume or directory. The device should contain a volume if it is a streamer or magnetic
			tape, or if the source and destination devices have different sizes, and the destination device is not an
			entered directory while the source is.

			The ANSI labels of a destination volume are then generated as follows:

	== Product number ==		== Product number ==

Tingo: /* Second file header label */ maximum byte pointer, in ASCII

2020-05-19T08:17:32Z

Second file header label: maximum byte pointer, in ASCII

← Older revision		Revision as of 08:17, 19 May 2020
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	- Up to 16 alphanumeric characters, starting from position 16, identifying the owner of this file. If the name is shorter than 16 characters, an apostrophe is used to mark the end of name.		- Up to 16 alphanumeric characters, starting from position 16, identifying the owner of this file. If the name is shorter than 16 characters, an apostrophe is used to mark the end of name.

	- 32-41 ~~contains~~ the ~~MAX BYTE POINTER~~ of the file.		- 32-41 contain an ASCII representation of the maximum byte pointer of the file.

	==== End of file label ====		==== End of file label ====

Tingo: /* First file header label */ add description of field 13

2020-05-19T08:13:32Z

First file header label: add description of field 13

← Older revision		Revision as of 08:13, 19 May 2020
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	54 11 accessibility 1 (space)		54 11 accessibility 1 (space)
	55-60 12 block count 6 000000		55-60 12 block count 6 000000
	61-73 13 system code 13 ~~(spaces)~~		61-73 13 system code 13 SINTRAN III x
	74-80 14 (not used) 7 (spaces)		74-80 14 (not used) 7 (spaces)

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	- Creation and expiration dates are not used, and the fields will contain spaces.		- Creation and expiration dates are not used, and the fields will contain spaces.

			$ field 13:

			- The system code is SINTRAN III x, where x is the version code, for example J<ref>{{ND-doc\|60.250.1 EN}} page 132</ref>.

	==== Second file header label ====		==== Second file header label ====

Tingo: /* First file header label */ any -> only

2020-05-19T08:09:50Z

First file header label: any -> only

← Older revision		Revision as of 08:09, 19 May 2020
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	$ field 7:		$ field 7:

	- ~~Any~~ alphanumeric characters. The field is left justified, and an apostrophe is used to mark the end of the string. The character code in this field identifies a backup generation of files.		- Only alphanumeric characters. The field is left justified, and an apostrophe is used to mark the end of the string. The character code in this field identifies a backup generation of files.

	$ field 8:		$ field 8:

Tingo: /* Label format on magnetic tape volumes */ corrected file data description

2020-05-19T07:59:21Z

Label format on magnetic tape volumes: corrected file data description

← Older revision		Revision as of 07:59, 19 May 2020
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	However, some deviations from the standard have been made. Deviations are marked by a dollar sign ($) in the explanation.		However, some deviations from the standard have been made. Deviations are marked by a dollar sign ($) in the explanation.

	General rules:		=== General rules ===

	- The general tape layout is as follows:		- The general tape layout is as follows:
Line 40:		Line 40:
	- All information in the labels is recorded as ASCII characters with the parity bit cleared. All unused character positions will contain spaces. $ The user option field (3) in the label UHL1 contains binary information.		- All information in the labels is recorded as ASCII characters with the parity bit cleared. All unused character positions will contain spaces. $ The user option field (3) in the label UHL1 contains binary information.

	- File data is recorded as ~~204~~ character blocks. These blocks may contain any character (0-255).		- File data is recorded as I * 2048 character, blocks where I is an integer from 1 to 8. These blocks may contain any character (0-255)<ref>{{ND-doc\|60.250.1 EN}} Appendix A, General rules</ref>.

	$$$$ Deviation From Standard		$$$$ Deviation From Standard

Tingo: added description of Organisation of files on storage media

2020-05-19T07:46:28Z

added description of Organisation of files on storage media

← Older revision		Revision as of 07:46, 19 May 2020
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	== Storage media for backup ==		== Storage media for backup ==
	The storage media for backup copies of files are hard disks, floppy disks, magnetic tapes or streamer tapes.		The storage media for backup copies of files are hard disks, floppy disks, magnetic tapes or streamer tapes.

			== Organisation of files on storage media ==
			Depending on how files are organised on storage media they are said to reside on a DIRECTORY or on a VOLUME.
			Files stored on hard disks must be stored on a DIRECTORY, files on floppy disks can either be stored on a DIRECTORY or on a VOLUME whereas files stored on magnetic tape will only be stored on a VOLUME.

	== Label format on magnetic tape volumes ==		== Label format on magnetic tape volumes ==