Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!ames!haven!umbc3!umbc5.umbc.edu!cs472226
From: cs472226@umbc5.umbc.edu (David Wood (CS472226))
Newsgroups: comp.lang.forth
Subject: Re: File handling tips
Summary: Other reasons for the BLOCK file
Message-ID: <1868@umbc3.UMBC.EDU>
Date: 5 Apr 89 12:23:38 GMT
References: <astroatc!nicmad!madnix!rat@SPEEDY.WISC.EDU> <8904040204.AA21175@jade.berkeley.edu>
Sender: newspost@umbc3.UMBC.EDU
Reply-To: cs472226@umbc5.umbc.edu.UUCP (David Wood (CS472226))
Organization: University of Maryland Baltimore Co.
Lines: 55

ZMLEB@SCFVM.BITNET (Lee Brotzman) writes:
>>David Phillip Oster (oster@dewey.soe.berkeley.edu.UUCP) writes:
>>|
>>| One advantage of traditional "blocks" over files:
>>|
>>| When your program crashes during LOAD, it is easier to fix it up and
>>| continue, rather than FORGETing everything and restarting the load:

 (((stuff about MacForth structuring deleted)))

>   I don't know about MacForth, but, in my experience, block-oriented Forth
>systems that run under host operating systems usually implement blocks as
>1024-byte fixed-length records.  There are no intervening end-of-line
>characters or other record terminators.  They are not at all like standard
>text files, as evidenced by trying to print them and getting a run-on
>mish-mash.
>   The reason I use blockish files while using Forth under MS-DOS, or Apple
>ProDOS, or VAX VMS (our Forth system is implemented under all three plus a
>few others) is for fast access to any part of the code.  When an error occurs
>I type WHERE and the editor puts my cursor at the point of the error.  Or, if
>I leave the editor, I type RESUME and I'm right back where I left off.  It's
>a simple matter to vector the system words to invoke these functions
>automatically, I just haven't found it important enough to do.

   There are a few other reasons for using the BLOCK-oriented file under
a host operating system:
   1> Some FORTHs (at least GS16Forth that I know of) will allow you to
restrict the size of your dictionary, declare a startup word, and save
the system image to disk. The result: An independent application which
you can run from whatever shell you please. If the system uses its OWN
operating system, you can't save it and run it from your standard
operating system.
   2> With the more frequent introduction of mass storage devices, the
typical block arrangement becomes impractical. A 1024-byte block was
just ducky for a 5&1/4" diskette which would hold 100-200K, but with the
3&1/2"s (which hold 800K+) and hard disks (which hold some number of
megs multiplied by ten), searching for screens unless you programmed in
a directory screen in some prominent location becomes a real pain.
   3> Not all FORTHOSes have communications systems, so they can't
really send or receive files too well. By using a file storage protocol
that Whatever-Term 4.19 can read, you can exchange code with other
people. (By the way... How goes the call for comp.forth.binaries?)
   4> It may be only as fast as the native operating system accesses it,
but considering the advantages above, it's worth it to sacrifice a
little speed to get the features.

   And now for something completely different...
   I'm looking for string-handling words, including variables,
constants, LEFT$, RIGHT$, MID$, etc... Could anyone tell me where to get
a collection like that? Are there any books with collections of routines
in FORTH that I should know about but don't because I'm lazy?

                                                 -David Wood
   Help! This account turns into a pumpkin in May! Where and how else
can I stay in touch with UseNet?