407 magic number (was: Referencing through a null pointer)

[Doug Gwyn]

In article <1988May6.165741.633 at utzoo.uucp> henry at utzoo.uucp (Henry Spencer) writes:
>This may have been aimed at things like standalone diagnostics rather
>than normal Unix programs, ...

Yes, it was also useful for bootstraps that had to fit entirely into one
512-byte block.  That way no code had to be "wasted" to skip the header
when rolling an a.out into memory, and the result could be started by
branching to its first location.