🚀 go-pugleaf

In <id.5POV.SIJ@ferranti.com> peter@ferranti.com (peter da silva) writes:

>In article <jdd.723756690@cdf.toronto.edu> jdd@cdf.toronto.edu (John DiMarco) writes:
>> "Closed systems" means proprietary systems (i.e. a system with hardware 
>> and/or software available only from one vendor). 

>So, if I'm running under Ultrix on a VAX it's a closed system (hardware and
>software available from only one vendor), but if I'm running under SunOS on
>a Sparc-2 it's an open system (since I can buy a Solbourne)? Even if I'm
>running the same application? What if I can run the same application on
>OpenVMS? What if another application only runs on SunOS because it needs
>NeWS or some other SunOS-only software component?

"Openness" is relative. Ultrix on a VAX is more "open" than VMS on a VAX,
since you can replace the Ultrix/VAX combination with some other 
UNIX-type OS/workstation combination with less pain than you can the VMS/VAX
combination. SunOS on a SPARC-2 is more open than these, because you can 
replace SunOS with stock SVR4 (eg. from ICL), and the SS2 with a SS2 clone, 
with even less pain. 

This leads to the following definition: "Openness" is essentially a measure of
the minimum migration cost of replacing a system with another from a different
manufacturer.

Note that calling Suns running SunOS "open" is a misleading thing, because in 
comparison to a 386 running DOS (where you can change OS from MS-DOS to
DR-DOS and system units from one manufacturer to another without recompiling 
your apps or retraining your users), suns are not really that open.

>Any system is only open where it exposes standard interfaces to applications,
>users, and other systems.

Standards are the means, "open" is the result.

John
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John DiMarco                                              jdd@cdf.toronto.edu
Computing Disciplines Facility Systems Manager            jdd@cdf.utoronto.ca
University of Toronto                                     EA201B,(416)978-1928