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- atapi.FAQ - Your most frequently asked questions about
- ATAPI/IDE CDROM drives.
-
- Author: Mathew E. Kirsch
- Systems Manager - Computing Graphics Engineering Technology
- SUNY at Alfred, Alfred NY 14802
- kirschm@snyalfva.cc.alfredtech.edu
-
- Revisions:
- 1.0 - First public posting, 951010
- 1.1 - Added Q5 and Q6, 951011
- 1.2 - Added Q7, courtesy Steve Clarke; renamed the ATAPI CDROM FAQ
- 1.3 - Added Q8, due to number of people with this problem
-
- Q1: Is the <Insert your brand/model here> IDE CDROM drive supported?
-
- A1: Yes, of course it is. It is an ATAPI/IDE CDROM drive, meaning it utilizes
- the IDE hard drive interface that is present in most typical home PC's
- today. It has been like this since kernel version 1.1.85.
-
- Q2: I already have two IDE hard drives. Will my ATAPI CDROM still work?
-
- A2: Yes, but you need to have a second IDE interface card to make it work.
- Unfortunately, not just any IDE card will work. The secondary interface
- card that you choose must have jumper-selectable IRQs and base addresses,
- or, you need to purchase a card that is specifically manufactured for
- use as a secondary interface. One such card is the Data Technologies
- model 2183. Its typically only $15, so its not a big expenditure on your
- part. If you bought a Mitsumi with an interface card, use that one.
- Another option is an EIDE card with dual IDE "ports", meaning it has
- two IDE/EIDE interfaces on the same card. I've been out of circulation
- for a while USENET-wise, but I heard that the 1.3.x kernels fully support
- EIDE interfaces.
-
- Q3: I can't seem to find the driver for the FX400 in the kernel source,
- what should I be looking for?
-
- A3: There isn't a SPECIFIC driver for the Mitsumi FX400 (or for any other
- ATAPI/IDE CDROM drive for that matter). What you need is the ATAPI
- CDROM driver that has been included in the kernel source officially
- since at least kernel version 1.1.85. It can be enabled just like any
- other driver when you "make config" and recompile the kernel. Recompiling
- the kernel is an entire FAQ in itself, so I won't cover it here.
-
- Q4: What options should I enable so I can use my new
- <insert brand name/model here> ATAPI CDROM?
-
- A4: Here is an excerpt from the "make config" sequence:
-
- *
- * Please see drivers/block/README.ide for help/info on IDE drives
- *
- Use old disk-only driver for primary i/f (CONFIG_BLK_DEV_HD) [n] n
- Use new IDE driver for primary/secondary i/f (CONFIG_BLK_DEV_IDE) [y] y
- Include support for IDE/ATAPI CDROMs (CONFIG_BLK_DEV_IDECD) [n] y
-
- As you can see, you do NOT want to use the old disk-only driver, and you
- DO want to use the new IDE driver and include support for ATAPI CDROMs.
- Also, make sure you enable ISO9660 filesystem support (the standard
- CDROM filesystem type). Compile your kernel, and copy the compressed kernel,
- vmlinuz, from /usr/src/linux/arch/i386/boot to / and do the same for
- System.map. If you are using an older version of Slackware (older than 2.2),
- you also need to run a short script to create the device nodes (in /dev)
- for the two devices on that secondary interface. The script is located in
- /usr/src/linux/drivers/block, and is called MAKEDEV.ide1.
- Update LILO or loadlin (whichever you prefer to use) as needed,
- reboot and away you (should) go. As long as you have your secondary IDE
- interface on IRQ 15, and at port address 170h-177h (the defaults for the
- DTC 2183 interface, but always double-check factory jumper settings, and
- as always: when in doubt, ask someone), things should work admirably.
- Linux should have no problem recognizing the secondary interface, and your
- bootup sequence should look something like this:
-
- hda: WDC AC1210F, 202MB w/64KB Cache, CHS=989/12/35, MaxMult=16
- hdb: Maxtor 7345 AT, 329MB w/64KB Cache, CHS=790/15/57, MaxMult=32
- hdc: FX400_02, ATAPI, CDROM drive
- ide1: secondary interface on irq 15
- ide0: primary interface on irq 14
-
- This may seem a bit confusing, so I'll translate. The first line indicates
- that my first hard drive (/dev/hda) is a Western Digital 202MB hard drive.
- The second is a Maxtor 329MB drive. hda is the first drive on the first
- interface, and hdb is the second drive on the first interface. hdc is the
- first drive on the second interface, and hdd (not used on my system, yet :)
- is the second drive on the second interfae. The third line, therefore,
- indicates that there is an FX400 ATAPI CDROM located on the first device
- of the second interface. The final two lines indicate that there are two
- IDE interfaces, one on IRQ 15, one on IRQ 14. The drives you have will
- show up differently, but the format will be the same. Remember where the
- CDROM was recognized, as you will have to make a symbolic file link to the
- /dev/cdrom device. Do this by typing (from anywhere):
-
- ln -s /dev/hdc /dev/cdrom
-
- Once booted, you should now be able to insert your favorite Slackware
- distribution CDROM and mount it by typing:
-
- mount /dev/cdrom /mnt
-
- Pretty simple, eh?
-
- Note that in some cases you may have to add the following line to your
- /etc/lilo.conf or to your loadlin script (whichever you use):
-
- append="hdc=cdrom" <--- for lilo.conf
- hdc=cdrom <--- from the lilo "boot:" prompt
-
- Q5: I've installed the drive as the only device on the secondary interface,
- with the CDROM drive jumpered as SLAVE/SINGLE, and Linux won't
- see it. What am I missing?
-
- A5: Well, quite a lot, to be frank. 99.99% of the ATAPI CDROM drives
- are shipped jumpered as SLAVE or SINGLE, and this simply will
- not work with Linux. By the IDE standard, a single
- drive on an interface must be jumpered as MASTER. There isn't (or
- shouldn't be) a specification for SINGLE in the IDE standard.
- Change the jumper on the back of the CDROM drive to MASTER,
- and follow the directions in Question 4, and you should be set to go.
-
- Q6: I've heard that putting my ATAPI CDROM and my IDE hard drive on the same
- IDE channel slows down the hard drive. What is the story?
-
- A6: From my personal experience (and the experience of several others who
- commented on the subject), there is no truth to the rumor that putting
- the CDROM and HDD on the same channel slows things down.
- The rumor states that the MEDIA TRANSFER RATE is set to the speed of
- the slowest device on the IDE channel. This is wrong.
- The real rumor should be that the INSTRUCTION TRANSFER RATE is set
- to the speed of the slower device on the IDE channel. Since the
- instructions are handled in firmware (the logic chips on the control
- boards on the drives) rather than on the spinning media, the only
- reason the INSTRUCTION TRANSFER RATE would be slower on one device
- is due to a poor design by the manufacturer.
- You mileage may vary here, because the rumor may actually be true
- if you're using certain IDE/EIDE controller boards. If you are
- experiencing the slowdown when your CDROM and HDD are on the same
- IDE channel, send the brand and model of your controller to me,
- and I'll list it here.
-
- Q7: I just got kernel 1.3.(19-30), and my ATAPI CDROM quit working. Why?
-
- A7: Somebody reworked the IDE/ATAPI drivers for kernel versions
- 1.3.19 through 1.3.30, and they got broken in the process.
- Don't ask me why, because as I see it, if it ain't broke, don't
- fix it! Another view on the subject is: If you don't want to be a
- guinea pig, don't get the odd-numbered (1.1.x, 1.3.x, 1.n.x) kernels.
- Stick to the even numbered, or production kernels, like 1.2.13.
-
- Q8: Why does my Mitsumi FX401 drive perform badly?
-
- A8: Mitsumi recently (about August '95) replaced the FX400 with the FX401.
- This model, although similar, has a few new minor features and a small speed
- increase. Unfortunately, the timing of this drive is slightly different and
- breaks the standard IDE/ATAPI controller in Linux 1.2.* - 1.3.26 with some
- EIDE controllers. The symptoms are break activity of the CDROM drive followed
- by about 10 seconds pause and an timeout/reset error message in a syslog
- file. The only known solution to this problem is to upgrade to a new
- development kernel 1.3.28 or later. The new code is stable in 1.3.30.
- Unfortunately, this new code doesn't work with several other drives.
- <thanks to steven.clarke@keble.oxford.ac.uk for Q7/A7>
-
- Q9: I just got finished wiring up my Sound Blaster 16 IDE, and the ATAPI drive
- isn't detected!
-
- A9: The most likely result of your troubles has to do with the base addressing
- of the IDE port on the Sound Blaster. This comes from the factory set to
- use the TERTIARY (third. Yes, there is a third and fourth IDE port now, but
- so far linux doesn't use them in the latest production kernel.) IDE port.
- Remember that for linux to see a second IDE port, it has to be at the
- secondary address (0x170-0x177, IRQ 15). This is the only way production
- Linux will ever see your second interface and ATAPI CDROM.
- You can also change a couple of lines in ide.c in the kernel source
- to probe for your secondary IDE card at the tertiary address/IRQ, but
- that's only for the adventurous.
- A second cause of your problem may be the fact that when Creative Labs
- manufactures a CDROM drive, they put the master/slave jumper on the
- SLAVE pins. It is pretty likely that the CDROM drive is the only
- device on the SoundBlaster IDE interface, and by the definition
- of the IDE standard, a single device on any given interface MUST
- be jumpered as MASTER. This doesn't bother DOS or any of the other
- inferior operating systems, because they are forgiving with regard
- to the manufacturer and user screw-ups. Linux is an operating system
- for someone that knows their computer fairly well, and it adheres
- to standards STRICTLY.
- You will also have to reconfigure your ATAPI CDROM and SB16IDE in
- DOS, Win 3.1x, Win 4.x, and OS/2, because the change of address won't
- be realized by these inferior (IMHO) operating systems.
-
- Epilogue: If you have any comments, questions, additions and/or corrections,
- let me know. I can be reached at kirschm@snyalfva.cc.alfredtech.edu,
- at my brother's email vp24njcb@ubvms.cc.buffalo.edu, or at a new site
- kirschm@london.cgt.alfredtech.edu (hopefully by late August, this will be
- my main address).
- I will periodically update this listing with new questions, and
- contributions, and I hope that it will eventually grow into a general
- ATAPI FAQ.
-
- Cheers
-