Number: 912

Date:  1-May-84 18':39':43

Submitter: Sannella.PA

Source: Masinter.pa

Subject: Document format of Alto .DM files (as produced by DUMPLOAD)

Assigned To: 

Attn: documentation

Status: Open

In/By: 

Problem Type: Documentation

Impact: Minor

Difficulty: Moderate

Frequency: Everytime

Priority: Unlikely

System: Other Software

Subsystem: Other

Machine: 

Disk: 

Lisp Version: 

Source Files: 

Microcode Version: 

Memory Size: 

File Server: 

Server Software Version: 

Disposition: 

Description: '
Date': 15 Apr 84 16':30 PST'
From': Masinter.pa'
Subject': [Ron Newman <Newman.es>': Re': The Structure of .DM files]'
To': LispSupport'
cc': vanMelle'
'
'
should be included in documentation of DUMPLOAD, suitably edited'
'
Subject': Re': The Structure of .DM files'
Dump file format is described in section 5 (the last two pages) of [indigo]<AltoDocs>Executive.TTY.   For your convenience':'
'
5. Dump Format'
'
'
A dump file is a sequence of blocks of eight-bit bytes. The  first byte'
of each block is the block type. A typical dump file might look like':'
        <name block><date block><data block 1>...<data block n>'
      .'
      .'
      <name block><date block><data block 1>...<data block m>'
      <end block>'
'
Name Block - Type=#377'
'
A name block  contains two bytes of  file attributes and then  the file name. (Ignored by load, set to 0 by Dump).'
'
Data Block - Type=#376'
'
A data block contains two bytes of byte count (high-order  byte first), two bytes of checksum (high-order  byte first), and a sequence  of data bytes.  The  byte  count  must  be  less  than  or  equal  to  256  for compatibility with Novas, and  the count does not include  the checksum or byte  count; only the  data bytes are  counted.  The checksum  is a 16-bit  add ignoring carry,  over the data and byte count. If the block has an odd number of bytes,  the last byte is NOT included in the checksum computation.'
'
End Block - Type=#374'
'
An end block has no contents and terminates a Load.~.'
'
Date Block - Type=#373'
'
Date blocks  with six bytes  of date are  generated; contains the four byte Alto creation date into the first  four bytes and  zeros  the  remaining  two.  Date blocks are optional.

Workaround: 

Test Case: 

Edit-By: Masinter

Edit-Date: 13-Jul-84 16':55':36