China DOS Union

Ask: How to use batch processing to determine whether a certain sector is an idle sector?

For example, after I use software to read sector 39, the obtained file is 039.txt, and the format is as follows:
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Disk 0 Absolute Sector 39
00000004E00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000004E10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000004E20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000004E30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000004E40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000004E50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000004E60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000004E70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000004E80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000004E90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
。。。。。
Omitted

－－－－－－－－－－－－－－－－－－

The batch processing I used is as follows, please help everyone to see, where is the problem.
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rem @echo off
if exist %temp%\039.txt del %temp%\039.txt >nul
diskrw 0 39 1 /l >%temp%\039.txt
For /f "tokens=1-2 delims=:" %%i In ('type %temp%\039.txt ^| find ":"') do (
set sector=%%j
echo sector is "%sector%"
pause
if not "%sector%"==" 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 " goto sector_2c
)

:sector_2d
echo Sector 39 is an idle sector.
echo.
pause
goto sector_2b

:sector_2c


echo Sector 39 is not an idle sector.
echo.
pause
:sector_2b

[ Last edited by lianjiang2004 on 2007-6-4 at 05:00 PM ]

The read - out "%sector%" has no value, I don't know why.

Variable delay is not enabled. Add "SetLocal EnableDelayedExpansion" at the beginning of the batch, then try changing %sector% to !sector!. If it doesn't work, post a follow-up to discuss.

Still no value. Just displayed as sector is "!sector!".

Even if all data is 0 it does not guarantee that this sector is unused nor does it guarantee that this sector will not be used so this can only be an auxiliary judgment method and other methods are still needed for the main judgment

Originally posted by qzwqzw at 2007-6-4 18:16:
Even if all data is 0

It does not guarantee that this sector is unused

Nor does it guarantee that this sector will not be used

So this can only be an auxiliary judgment method

Other methods are still needed for the main judgment

Please teach me what the main judgment method is?
I want to use an idle sector in a reserved sector.
General software will not use it, and I think there is no need to guarantee that it will not be used. Hehe, just like others can use it, I can also use it. I think as long as it is not used yet.

Originally posted by lianjiang2004 at 2007-6-4 17:20:
Still no value. Just displayed as sector is "!sector!".

Helped you test it, it's okay!
sector is " 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00"
Press any key to continue...
Sector 39 is not an idle sector.
Press any key to continue...

How could there be none?

It tests normally here.

@echo off

SetLocal EnableDelayedExpansion

For /f "tokens=1-2 delims=:" %%i In ('type 009.txt ^| find ":"') do (

        set sector=%%j

        echo sector is "!sector!"

        pause

        if not "%sector%"==" 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 " goto sector_2c

)

pause

Strange thing, copied the content from the 8th floor, and there are values.

What I want is to display only the lines that are not "00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00" as non-free sectors. Why are all 0s also displayed as non-free sectors? What's wrong in my batch script?

Got it, it should be changed to if not "!sector!" == "00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00" goto sector_2c

Ask, why must the beginning part add "SetLocal EnableDelayedExpansion"? The similar batch processing I used before didn't need it. Just like the batch processing in building 1.

Search for the keyword "variable delay".

It's more convenient to remove the first pause.

Because the batch processing didn't pass, so I'm checking for errors, which has resulted in more display areas. I found that the variable there has no value, so I came to ask for help. Once solved, of course, I need to remove the useless information and just get the result. Thanks a lot.