DUMPER tape format - Revision history

Larsbrinkhoff: /* TAPE HEADER */ Format 5-6 has seven more fields.

2025-01-22T11:57:23Z

‎TAPE HEADER: Format 5-6 has seven more fields.

2022-04-27T10:29:37Z

‎DATA RECORD: It's all file data.

2022-04-27T10:16:37Z

‎FILE HEADER: More info.

2022-04-27T07:25:11Z

‎RECORD HEADER: Update MINI-DUMPER sequence numbering.

2022-04-15T06:56:48Z

‎FILE HEADER

2022-04-15T06:54:21Z

‎TAPE TRAILER: I see no data here.

2022-04-15T06:50:41Z

‎FILE TRAILER

2022-04-15T06:44:43Z

‎TAPE HEADER

2022-04-14T14:16:52Z

‎TAPE FORMATS

2022-04-14T14:16:05Z

‎TAPE FORMATS: Match format number to operating system releases.

@@ Line 124: / Line 124: @@
 |-
 | 7
-| "BFMSG" - offset from header to start of saveset name?
+| "BFMSG" - offset from header to start of saveset name.
 |-
 | 8
 | [[Timestamp]] for saveset.
 |-
 | 6+BFMSG

← Older revision		Revision as of 10:29, 27 April 2022
Line 106:		Line 106:

	===DATA RECORD===		===DATA RECORD===
		+
		+	All 512 words after the header is file data.

	===TAPE HEADER===		===TAPE HEADER===

@@ Line 133: / Line 133: @@
 ===FILE HEADER===
-In format 0, the only file header data is an ASCIZ string in the format DEV:<DIRECTORY>NAME.TYPE;VERSION;P123456;AUSER.
+In format 0, the only file header data is an ASCIZ string in the format ''DEVICE''''':<'''''DIRECTORY'''''>'''''NAME'''''.'''''TYPE''''';'''''VERSION''''';P'''''PROTECTION''''';A'''''ACCOUNT''.
 Other formats use a period instead of semicolon before the version, and have an FDB (file descriptor block) at offset 0200 (octal) from the record header.

@@ Line 79: / Line 79: @@
 The [[checksum]] is computed over all 518 words in the record, with the checksum set to 0.  For formats 0-4, it's a [[one's complement]] sum.  For format 5-6, it the sum is first rotated one step to the left and then adding in the data.  The finished checksum is bit-wise inversed before being stored in the header.
-MINI-DUMPER expects the sequence number to start with 2, whereas later versions begin with 1.  Normally each record increments the sequence number by 1, but a MINI-DUMPER tape header increments it by 2.
+MINI-DUMPER expects the sequence number to start with 2, whereas later versions begin with 1.  Each record increments the sequence number by 1; MINI-DUMPER also have tape marks increment it.
 {| class="wikitable"

@@ Line 135: / Line 135: @@
 In format 0, the only file header data is an ASCIZ string in the format DEV:<DIRECTORY>NAME.TYPE;VERSION;P123456;AUSER.
-Other formats have an FDB, file descriptor block at offset 0200 (octal) from the record header.
+Other formats use a period instead of semicolon before the version, and have an FDB (file descriptor block) at offset 0200 (octal) from the record header.
 ===FILE TRAILER===

← Older revision		Revision as of 06:54, 15 April 2022
Line 142:		Line 142:

	===TAPE TRAILER===		===TAPE TRAILER===
		+
		+	This record only marks the end of the saveset and has no data. After this record there should be a tape mark to end the file.

	===USER DIRECTORY===		===USER DIRECTORY===

← Older revision		Revision as of 06:50, 15 April 2022
Line 138:		Line 138:

	===FILE TRAILER===		===FILE TRAILER===
		+
		+	The data is the FDB, file descriptor block. In format 0, this is 25 (octal) words. Newer format has 30 (or more?) words.

	===TAPE TRAILER===		===TAPE TRAILER===

@@ Line 109: / Line 109: @@
 ===TAPE HEADER===
-In format 0, the data is just an [[ASCIZ]] saveset name.
+In format 0, the data is just an [[ASCIZ]] saveset name at record offset 6.
 If format 4, the data is:

@@ Line 13: / Line 13: @@
 ===TAPE FORMATS===
-There is a tape format number stored in the tape header.  It more or less corresponds to the TOPS-20 release.  MINI-DUMPER is retroactively assigned format number 0, and doesn't have the format number stored in the tape header.
+There is a tape format number stored in the tape header.  It corresponds roughly to the TOPS-20 release.  MINI-DUMPER is retroactively assigned format number 0, and doesn't have the format number stored in the tape header.
 {| class="wikitable"

@@ Line 19: / Line 19: @@
 | Format
 | Description
 |-
 | 0
 | [[Bolt, Beranek, and Newman|BBN]] original MINI-DUMPER format.
 |-
 | 3
 | FDB changes, structures, "full dir spec".
 |-
 | 4
 | New GTDIR blocks.  Lowest legal format for latest DUMPER.
 |-
 | 5
 | Encrypted passwords and other "CRDIR%iods".
 |-
 | 6
 | "TONEXT" record type.
 |}