checksum importance

pheidius12 · ‎07-02-2010

I have a cisco 3620. I just attempted to copy my

Sim flash image to a new 20 MB PMCIA flash

Router#show version
Cisco Internetwork Operating System Software
IOS (tm) 3600 Software (C3620-IS-M), Version 12.1(3a)T7, RELEASE SOFTWARE (fc1)

TAC Support: http://www.cisco.com/cgi-bin/ibld/view.pl?i=support
Copyright (c) 1986-2001 by cisco Systems, Inc.
Compiled Sat 10-Mar-01 19:45 by ccai
Image text-base: 0x60008950, data-base: 0x6102E000

ROM: System Bootstrap, Version 11.1(20)AA2, EARLY DEPLOYMENT RELEASE SOFTWARE (f
c1)
ROM: 3600 Software (C3620-IS-M), Version 12.1(3a)T7, RELEASE SOFTWARE (fc1)

Router uptime is 1 hour, 11 minutes
System returned to ROM by power-on
System image file is "flash:c3620-is-mz.121-3a.T7"

cisco 3620 (R4700) processor (revision 0x81) with 49152K/16384K bytes of memory.

Processor board ID 29853621
R4700 CPU at 80Mhz, Implementation 33, Rev 1.0
Bridging software.
X.25 software, Version 3.0.0.
SuperLAT software (copyright 1990 by Meridian Technology Corp).
2 Ethernet/IEEE 802.3 interface(s)
1 Serial network interface(s)
DRAM configuration is 32 bits wide with parity disabled.
29K bytes of non-volatile configuration memory.
16384K bytes of processor board System flash (Read/Write)
20480K bytes of processor board PCMCIA Slot0 flash (Read/Write)

Configuration register is 0x2102

     Size(b)     Free(b)      Type Flags Prefixes
       30712       30136     nvram     rw   nvram:
           -           -    opaque     rw   null:
           -           -    opaque     rw   system:
           -           -   network     rw   tftp:
*   16777216     6839256     flash     rw   flash:
    20971520    20971520     flash     rw   slot0:
           -           -     flash     ro   slot1:
           -           -    opaque     wo   lex:
           -           -    opaque     ro   xmodem:
           -           -    opaque     ro   ymodem:
           -           -   network     rw   rcp:
           -           -   network     rw   pram:
           -           -   network     rw   ftp:

So I made the copy command:

Router#copy flash:c3620-is-mz.121-3a.T7 slot0:c3620-is-mz.121-3a.T7
erase n

CCCCC ect.

but the check sum failed

Verifying checksum... invalid (expected 0xBC40, computed 0x3E95)
9937896 bytes copied in 195.640 secs (50963 bytes/sec)
Router#how version

so dir commands:

Router#dir flash:
Directory of flash:/

1 -rw- 9937896 <no date> c3620-is-mz.121-3a.T7

16777216 bytes total (6839256 bytes free)
Router#dir flash0:
Directory of flash:/

1 -rw- 9937896 <no date> c3620-is-mz.121-3a.T7

16777216 bytes total (6839256 bytes free)
Router#

So how important is the checksum here before I move to set the register to boot from the PMCIA card.

Should I reformat erase the PMCIA card andf retry the copy or should I reformat /erase and try maybe copy running config commands instead?

Reza Sharifi · ‎07-02-2010

it seems that the copy was done successfully but it would not heard anything if you erase and format the PCMCIA card and copy it again. The other thing is that if you put the PCMCIA card in its slot and reboot the router it will try to boot from the PCMCIA card first and it can't find the image then it will boot from flash but you have to make sure that the image is on flash and it is working with no issues.

HTH

Reza

pheidius12 · ‎07-02-2010

Ok, I will try it from the reformat side/recopy first. This was supposedly a new card but you never know. Is there any chance that the simm image will expand slightly diferently in flash memory then Simm? The size in bytes is the same on both cards. I backed up the image before the first copy to my TFTP server plus I have another IOS that I can throw on the hardrive in the worst case. Would a running config copy be a better comparison as it would already be uncompressed? The router boots and has been running from the simm source with no known issues