Efficient representation of requirements flowdown?
FullBandwidth
Didn't see anything about this in the DOORS help file.
In any system, I might have top-level requirements that flow down (i.e.
are allocated) into specific subsystems. Those could take two forms:
(1) System-level requirements that flow down identically into each
subsystem;
(2) System-level requirements that are allocated in portions to each
subsystem, from which subsystem requirements might be derived at design
time.
For example, in a shipping system, a requirement like
(SYS-1) All product shall be protected from handling damage.
might be considered identical in all stages of handling - picking
(product from the warehouse shelf), boxing, filling (the box with
packaging material), taping (the box closed), labeling (mailing label)
and docking (putting the boxes on the loading dock for pickup by the
carrier). At every stage the system will be designed to prevent damage;
the specific means for implementing that requirement could be different
within each subsystem.
So first question - if I state SYS-1 as a requirement in my top-level
system specification module, is there an easy way to have it
"replicated" or "referenced" in each subsystem module? That way, if the
wording of the requirement changes at the top level, it automatically
changes in each subsytem module. This is different from traceability,
I think.
A requirement like
(SYS-2) Product shall be available for carrier pickup within 24 hours
of order placement.
I might allocate 6 hours to picking, 1 hour to boxing, 1 hour to
filling, etc. So each subsystem module would have a chunk of the 24
hours allocated to it. E.g.
(PICK-2) Product shall be picked within 6 hours of order placement.
(BOX-2) Product shall be boxed within 1 hour after completion of
picking.
etc.
Now I need a way of making sure that all my handling time requirements
somehow reference the SYS-2 requirement, such that if I decide to go to
a 12-hour requirement in SYS-2, I can easily see whether my derived
requirements (allocation) have to change. This perhaps is a typical
traceabilty case?
Are cases (1) and (2) fundamentally different or the same? That is,
when I flow down SYS-1 into the subsystem modules, should I redefine
the requirement specific to each subsystem such as:
(PICK-1) Product shall be protected from damage in the picking process.
(PICK-1.1) Picking shall not expose the product to damage from
dropping.
(PICK-1.2) Picking shall not expose the product to damage from
crushing.
etc.
(TAPE-1) Product shall be protected from damage in the taping process.
(TAPE-1.1) Taping shall not expose the product to damage from dropping.
assuming that once the product is in the box and filled with packing
material that it is by definition protected from crushing, however if
the box falls off a conveyor before it's taped closed, the product
could fall out and sustain damage.
I think treating cases (1) and (2) as separate and having a way to
represent case (1) without having to duplicate text is a more efficient
way, just wondering if DOORS provides some means for doing this?
Thanks