[comp.sys.cbm] autobooting from a 1581

dattier@jolnet.ORPK.IL.US (David W. Tamkin) (03/26/89)

Dave Funk wrote in <802@zehntel.UUCP> in comp.sys.cbm:

| Well, I did that, and it works!  The only thing I haven't quite figured
| out is how to also overwrite the first byte in the sector (seems this is
| reserved for the sector length).  It is a simple matter to use a disk 
| editor to do this, but I would prefer my program to handle it.  I know
| it can be done - disk editors do it and Fred Bowen's 'autoboot 128' program
| must do it.

It sounds as though you tried to use b-r and b-w instead of u1 and u2 (or ua
and ub).  The b-r and b-w commands were designed for a different purpose
from copying or editing sectors, and they will respectively reinterpret or
rewrite byte 0 of the sector.

u1 (aka ua) and u2 (aka ub) can handle whole sectors without reading
anything special into the meaning of byte  0.  That is how disk editors and
autoboot writers work.

On the 1581 you can use b-R and b-W to operate outside the current
subdirectory (note the shifted R and W).

David W. Tamkin     Post Office Box 567542    Norridge, Illinois  60656-7542
dattier@jolnet.orpk.il.us    Jolnet Public Access Unix     GEnie: D.W.TAMKIN
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Anyone on Jolnet who agrees with me is welcome to speak up on his or her own.