Date: Wed, 25 Aug 1999 03:54:48 -0500 From: Tim Tsai <tim@futuresouth.com> To: freebsd-small@freeBSD.ORG Subject: porting a DOS application (also DOC booting) Message-ID: <19990825035448.A17461@futuresouth.com>
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I am considering porting an embedded DOS based application to PicoBSD and I have a few questions. 1) is it possible to boot off the DiskOnChip (fla) driver? 2) I have 4 megs of DRAM - I am assuming that's sufficient. The application itself might take up as low as 512k but I'll be more comfortable with 1meg. 3) Can PicoBSD be configured relatively easily to run from a read-only partition (to minimize any possibility of corruption) or will I have to go the "run-off-MFS" route? 4) does anybody envision a problem sustaining 115,200 baud on COM1 on a 386sx-40? It has a 16550 UART and we'll most likely configure the receive FIFO to be 8 characters deep (that's what works best in DOS). 5) we're going to need to store data to both DOC and a PCMCIA ATA Flash card (the PCMCIA will have to a DOS partition). Since we preallocate space for all storage in a big file before operations, ideally we do not want any writes to the FAT table. I don't see any convenient flags in either mount_msdos or mount to do this. Any problems if I just modify the MSDOS driver to not bother writing just to update the time? (I hope it'll be a relatively easy thing!). 6) I've got a POS hardware that we must interface to that'll require about a 50 nanosecond sleep between byte writes. In DOS I have a carefully calibrated delay loop for this. What is a reasonable method to do this with FreeBSD? For this kind of delay on a 386, is there any point of even making system or kernel calls? Lastly, anything to keep in mind before I base a $10,000 product on FreeBSD? :-) Many thanks! Tim To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-small" in the body of the message
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