Dear List... I'm calling back with respect to the 4k-sector USB disk drive. I'm considering writing a loadable DOS 'block' driver for it, as Eric Auer suggested. My experience with programming DOS driver is unfortunately more on the side of character devices than block, so, please bear with basic questions for a moment if you please.
I would like to take the simplest approach possible first, even at the expense of performance. My driver would be little more than a 'shell' around USBASPI.SYS. Therefore my first interrogation is, what set of device header attributes - and associated functions, including IOCTL codes - must be present /at a minimum/ for letting DOS access the disk properly ? - For a tentative and probably naive self answer, could I get away with the driver attribute being all zeroes - and implement functions 0, 1, 2, 4, 8, 9 (alias for fn 8) /only/ ? Assuming this basic set of functions properly implemented, will the device work ? Do we /need/ 0D,0E (open/close) for instance ? - Using a loadable driver for the block device implies DOS won't use /its/ internal buffers, so I don't have to care about DOS own buffers sizing, right ? - Besides, should I consider using the "non IBM format" bit in driver attribute ? From whatever docs I saw is unclear what "non IBM" changes exactly in how DOS uses the driver, nor the (dis)advantages of that approach and the requirements it puts on (removes from) the driver. TIA ! -- Czerno ------------------------------------------------------------------------------ Try before you buy = See our experts in action! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-dev2 _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
