From owner-freebsd-small Wed Aug 25 1:56:31 1999 Delivered-To: freebsd-small@freebsd.org Received: from shell.futuresouth.com (shell.futuresouth.com [198.78.58.28]) by hub.freebsd.org (Postfix) with ESMTP id C9E26158C3 for ; Wed, 25 Aug 1999 01:56:24 -0700 (PDT) (envelope-from tim@futuresouth.com) Received: (from tim@localhost) by shell.futuresouth.com (8.9.3/8.9.3) id DAA17585 for freebsd-small@freeBSD.ORG; Wed, 25 Aug 1999 03:54:48 -0500 (CDT) Date: Wed, 25 Aug 1999 03:54:48 -0500 From: Tim Tsai To: freebsd-small@freeBSD.ORG Subject: porting a DOS application (also DOC booting) Message-ID: <19990825035448.A17461@futuresouth.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.95.3i Sender: owner-freebsd-small@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG 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