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Conditionally Loading .sys Files?

PostPosted: Sun Apr 02, 2017 3:28 pm
by Tempest
Is it possible through the use of autoexec.bat to conditionally load .sys files? I have a backpack (3.5" floppy) driver that I only need when I want to transfer things to my PCjr, otherwise it's taking up 13.5k of precious memory. Is it possible to put a statement in my autoexec to ask if I want to load the driver with a y/n prompt?

Re: Conditionally Loading .sys Files?

PostPosted: Sun Apr 02, 2017 4:14 pm
by Trixter
This was just discussed on the VCFED forums; I believe the product you're looking for (that works with any version of DOS) is BOOT.SYS. Look for "boot210.zip" online.

Code: Select all
BOOT.SYS v2.10 <ASP> - The Heavy-Duty Config
Manager. Gives you one or more menus out of
CONFIG.SYS, similar to DOS6. Adds pretty
menu, if/then/else, use of variables, and on-
the-fly editing in CONFIG.SYS; reboot from
cmd line; passwords; installation program
upgrades DOS6 multi-config; more! Does NOT
write to your disk! 20 items per menu/25
menus. DOS 2.11 to 6.3 (DR/NWDOS7, too),
DOS=, QEMM7. Auth: Hans Salvisberg

Re: Conditionally Loading .sys Files?

PostPosted: Sun Apr 02, 2017 4:15 pm
by Trixter
Keep in mind that jrconfig.sys boots twice as it runs (it adjusts memory, then warm-reboots so the new memory can be seen), so any branching fun you will do with boot.sys should likely be after jrconfig.

Re: Conditionally Loading .sys Files?

PostPosted: Sun Apr 02, 2017 4:43 pm
by Tempest
Interesting, I'll have to look into that.

How much memory is generally needed for PCjr games? I know back in the 486/Pentium era you needed 615K+ free but I doubt the memory requirements are that high for XT era software

Re: Conditionally Loading .sys Files?

PostPosted: Sun Apr 02, 2017 6:42 pm
by Trixter
All games that can run on the PCjr will run in CGA if you have a 640K system, or in PCjr/Tandy mode if you have a 736K system like with the jrIDE. You don't need to worry that much about free RAM unless you've got 100K in TSRs loaded or something. What I'm trying to say is that it won't come up in actual usage.

Re: Conditionally Loading .sys Files?

PostPosted: Sun Apr 02, 2017 7:29 pm
by Tempest
I guess I don't need to worry about the backpack driver then. I think I have about 578k or so free so I guess it should be ok.

One question though, is the reported free ram the total free ram or just the 'fast ram' not including the built in 128k? Because I'm curious as to what's eating up all that memory.

Re: Conditionally Loading .sys Files?

PostPosted: Sun Apr 02, 2017 8:58 pm
by Trixter
It's the total. If you want to see what is taking up memory, run CHECKIT, INFOPLUS, or (dos 5 or later) mem /c to see what loaded.

578K free is *quite good* for a 640k system (or a 768k system running jrconfig) so you really don't have to obsess over this.