About the L51_BANK.A51 file

You can use variable banking also on
classic 8051 devices. Take a look to the C51 Compiler PDF manual and take a look to
C:\Keil\C51\EXAMPLES\FarMemory\4MB Variables on Classic 8051

You can use variable banking also on
classic 8051 devices. Take a look to the C51 Compiler PDF manual and take a look to
C:\Keil\C51\EXAMPLES\FarMemory\4MB Variables on Classic 8051

Thanks your answer very much.

But I want to know can the L51_BANK.A51 file in keilC51 ver620 be used in previous version keilc51 like v602?

Thank you!

No that is not possible. The new features in L51_BANK.A51 require also new linker versions.