Sharp mz-3500 Manual For Use page 201

Section A: System interface
************************************************************************
* *
*
*
28 - Write Protect Drive *
*
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On entry:
On return:
c
DE
lCH
Possible logical errors:
- none -
Possible physical errors:
- none -
Differences to CP/M plus:
- none -
Differences to CP/M 2.2 resp.
Dicos:
- none -
A call of this function marks the current drive as write protected. The
protection can only be deleted by functions 13 or 37.
EOS System manual
Daeumling & Zimmermann
Page 64