Since https://github.com/zopefoundation/Zope/commit/2da2c2c28a8b21e78e8ef93aa17da926e3102c26
SERVER_PORT is assumed to be convertible to int.

The value of this port is not really supposed to be used because
TimerServer requests does not have a server (for example in CMFActivity
we recreate the initial request), so put a value of -1 to prevent
accidental use.

Only catch exceptions, we don't need a bare except here. In case of
exception, log the traceback instead of being silent.

This can happen if there is an error very early during publication.

we don't support negative quantity (it is better represented by an
inversion of source and destination), and this allows better support of
the smallest slice in ERP5, more especially in SupplyLine_asCellRange,
where the title of the cell is computed with the min and max being None
or not.

See nexedi/slapos.core!307 (b7d5041e)

The real issue is probably in the launcher.js file, but it is more tricky to fix

See nexedi/slapos.core!313 (b02b2bff)

These are clone of Computer and Computer Partition, but used for virtual
computing devices, unrelated to physical hardware.