EMULAB Forum

Please login or register.

Login with username, password and session length
Advanced search  

News:

The new forum is online, hope you enjoy it!

Pages: [1]   Go Down

Author Topic: Scanner does not check crc32?  (Read 85 times)

newuzer

  • Member
  • *
  • Karma: 0
  • Offline Offline
  • Posts: 13
  • Operating System:
  • Windows NT 10.0 Windows NT 10.0
  • Browser:
  • Firefox 87.0 Firefox 87.0
    • View Profile
Scanner does not check crc32?
« on: 08 April 2021, 09:11 »

Hi Roman,

I ran into something I can't explain with the scanner, while scanning a set with an old crc32 only datfile.
Attached a datfile and zip of the MAME 0.36 turbotag set.
The ttprog1.bin in the zipfile has crc b0505e18.
The datfile shows crc 4fafa1e7 for ttprog1.bin.
The size of the file is as it should be, 8192 bytes.

The rebuilder doesn't pick up the ttprog1.bin file, as expected.
However, if you scan the zipfile with ttprog1.bin included, it won't mark it as unneeded.
If you add an empty ttprog1.bin file to the zipfile, it will be marked as unneeded by size.

Why is this file not recognized by the scanner as unneeded by crc?

With kind regards, NU.
Logged


Roman

  • Global Moderator
  • Member
  • ***
  • Karma: 96
  • Offline Offline
  • Posts: 2932
  • Operating System:
  • Windows NT 10.0 Windows NT 10.0
  • Browser:
  • Chrome 89.0.4389.114 Chrome 89.0.4389.114
    • View Profile
Re: Scanner does not check crc32?
« Reply #1 on: 08 April 2021, 13:02 »

No everything is fine and of course the crc32 is checked.
But such old MAME versions used bitwise inverted crc32 values to mark a bad dump in the datfile.
So your file is actually ok (but  a marked bad dump):

4fafa1e7 = BOOLEAN-NOT b0505e18

There's an option in the profiler options to enable the inverted crc32 mode, then the rebuilder also rebuilds it.


Yeah...there are some weird things in 20 year old MAME versions....that's one of the reason why people should stick with the current one :)
Logged

newuzer

  • Member
  • *
  • Karma: 0
  • Offline Offline
  • Posts: 13
  • Operating System:
  • Windows NT 10.0 Windows NT 10.0
  • Browser:
  • Firefox 87.0 Firefox 87.0
    • View Profile
Re: Scanner does not check crc32?
« Reply #2 on: 08 April 2021, 13:14 »

Now it can be explained.
Thanks Roman!

With kind regards, NU.
Logged
Pages: [1]   Go Up
 

Page created in 0.115 seconds with 20 queries.

anything