OSDev.org

The Place to Start for Operating System Developers
It is currently Thu Mar 28, 2024 1:57 pm

All times are UTC - 6 hours




Post new topic Reply to topic  [ 18 posts ]  Go to page Previous  1, 2
Author Message
 Post subject: Re: Disk device driver: floppy disk or USB key?
PostPosted: Mon Jan 11, 2016 3:32 pm 
Offline
Member
Member

Joined: Sat Mar 01, 2014 2:59 pm
Posts: 1146
I seem to remember that Bochs had a "bug" in that the emulated FDC didn't care if it was properly calibrated. I remember that mine worked fine on Bochs but didn't work on real hardware, because I wasn't properly resetting the FDC.

_________________
When you start writing an OS you do the minimum possible to get the x86 processor in a usable state, then you try to get as far away from it as possible.

Syntax checkup:
Wrong: OS's, IRQ's, zero'ing
Right: OSes, IRQs, zeroing


Top
 Profile  
 
 Post subject: Re: Disk device driver: floppy disk or USB key?
PostPosted: Mon Jan 11, 2016 9:49 pm 
Offline
Member
Member

Joined: Mon Dec 21, 2015 7:09 pm
Posts: 38
Just be sure, when you guys talk about an ATA driver, you mean ATA using DMA, correct? (what is described on http://wiki.osdev.org/ATA/ATAPI_using_DMA)


Top
 Profile  
 
 Post subject: Re: Disk device driver: floppy disk or USB key?
PostPosted: Mon Jan 11, 2016 10:24 pm 
Offline
Member
Member
User avatar

Joined: Sat Jan 15, 2005 12:00 am
Posts: 8561
Location: At his keyboard!
Hi,

lpoulain wrote:
@Brendan: I don't expect anything to work the first time ;-) Developing your own OS is about perseverance (it took me weeks to get multitasking properly working). Sometimes though you're looking for the path which is likely to be the less painful.


Yes; but when I search your posts I don't see anything asking for help fixing a floppy driver, which tells me you haven't exhausted your options.

lpoulain wrote:
Just be sure, when you guys talk about an ATA driver, you mean ATA using DMA, correct? (what is described on http://wiki.osdev.org/ATA/ATAPI_using_DMA)


Typically you'd have a single ATA driver that supports all 4+ variations of DMA/bus mastering plus all 3+ variations of PIO; where that driver auto-detects which of these the controller supports, then identifies the disk drives are present and figures out which transfer rates each disk drive and its cable (see note) supports and decides which method to use for each disk drive.

Note: Yes, I'm serious, the cable matters. If there's a relatively modern controller, a relatively modern disk drive and an old 40-conductor cable, then you have to use slower data transfer methods to avoid data corruption even though both the controller and drive will support faster data transfer methods.


Cheers,

Brendan

_________________
For all things; perfection is, and will always remain, impossible to achieve in practice. However; by striving for perfection we create things that are as perfect as practically possible. Let the pursuit of perfection be our guide.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 18 posts ]  Go to page Previous  1, 2

All times are UTC - 6 hours


Who is online

Users browsing this forum: No registered users and 30 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group