From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on
	ip-172-31-74-118.ec2.internal
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=3.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
Path: eternal-september.org!reader01.eternal-september.org!feeder.eternal-september.org!feeder1.feed.usenet.farm!feed.usenet.farm!feeder.usenetexpress.com!tr1.eu1.usenetexpress.com!newsfeed.xs4all.nl!newsfeed8.news.xs4all.nl!nzpost2.xs4all.net!news.kpn.nl!not-for-mail
Subject: Re: Hardware independent programming
Newsgroups: comp.lang.ada
References: <5ef9712d$0$1221$e4fe514c@news.kpn.nl>
From: ldries46 <bertus.dries@planet.nl>
Date: Thu, 2 Jul 2020 08:15:20 +0200
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0
MIME-Version: 1.0
In-Reply-To: <5ef9712d$0$1221$e4fe514c@news.kpn.nl>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
Content-Language: en-GB
Message-ID: <5efd7b78$0$1434$e4fe514c@news.kpn.nl>
NNTP-Posting-Host: 2e01f686.news.kpn.nl
X-Trace: G=SnO2t5PK,C=U2FsdGVkX19XUYGkLGg5Sm+MKeRF9Gmx9cjn9xtp+0qQVr3UFgtGtcGmyuzfF3jtpBLCdQV3jGyEvJEMbhI00yD/sgANR5j+gLJrb2+c92Q=
X-Complaints-To: abuse@kpn.nl
Xref: reader01.eternal-september.org comp.lang.ada:59308
List-Id: <comp.lang.ada>

Op 29-6-2020 om 6:42 schreef ldries46:
> Hardware can in some cases have limits you have to consider when 
> writing a program.
>  At this moment I can mention three:
>
> 1. The printer. The format of the documents you want to print must fit
>    on the printers available to the user. In general the problem is
>    solved by the possibility of printer drivers to shrink you document
>    f.i. from A4 to A4 or saving the document to a file that can be
>    printed elsewhere.
> 2. The monitor on the system your program is running. Creating a window
>    that is to large for your screen resolution can be trouble some but
>    you do not know the resolution of the the customer using your
>    program. The solution for such a problem can only be hardware
>    independent programming. Your program should know the resolution of
>    your screen and adjust to  that or in the worst case decide that
>    system is not suitable for the program.
> 3. The available memory. Your program will in some cases need to know
>    the limits to which the heap stretches within the memory (in cases
>    where it is necessary  to use very large bulks of data). For
>    operating systems that have the possibility to stretch the heap with
>    a part on disc both boundaries (with and without disc data) are of
>    interest.
>
> There should be a package in Ada that like GNAT.OS-lib does with 
> operating system differences, makes such hardware parameters available 
> for the programmer.
>
If we want to create hardware or operating system independent programs 
it is in some situations necessary to use environmental variable from 
which a package in Ada or in other languages can get values from.
The names of these values should then in all these systems the same. I 
found that in Windows OS is such a variable for the name of the 
operating system (OS=Windows_NT) In Linux(Ubuntu) I could not find such 
a variable so it looks logical to use OS=Linux. For other parameters 
standard names should be found. So the ada packages I mentioned is not 
the only thing that must be done.