what is error "restart = 01"

[fmlin@terapin.com (Frank M. Lin)]

Subject says it all... what is "restart=$01" ( or "restart=01 ) in ProDOS 8?

I get this message when I load up ProTERM 3 sometimes.  One interesting thing
to note, If I keep the voltage at 5.4v, this message tend to go away, if I go
to about 5.5v or 5.6v, this message would come up very frequently.

Thanks.