40 vs 80 wire IDE cables for CD drives

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videobruce

1
I understand there are issues using 80 wire IDE cables for CD burners. It is suppose to be well known, but I haven't run into this yet or have seen any threads on the subject.

What is the deal, is there issues and what?
 
Duracell

Duracell

1
40 wire cables for UDMA 33 and UDMA 66 devices
80 wire cables for UDMA 100 and UDMA 133 devices

CD-ROM, DVD-ROM, CD-RW and DVD-RW drives aren't UDMA 100/133 devices;


Greetings from
Duracell
 
daveml

daveml

1
If u have an ata100/133 compatable motherboard u can use 80 wire cable for any IDE device.
There is no benefit in doing it for cd/dvd drives as far as I'm aware, but if thats the only spare cable u have then it will work perfectly fine.
All my drives are on 80 wire with no problems what so ever.
 
L

LTR12101B

1
Not Quite....
40 is good for modes up to ATA/33
80 is required for ATA/66 or above

Most controllers force a maximum of ATA/33 on a 40 wire cable - and this is the highest mode I've ever seen an optical device support.

If you are forced to share an cable between a HD of ATA/66 or better, and an optical device, an 80 wire cable is required - though I seem to recall that Ultra devices may be restricted to no more than ATA/33 if there is a non-Ultra device on the same cable - though this may be a myth derived from the 40/80 wire handling!
 
jorel

jorel

1
daveml said:
If u have an ata100/133 compatable motherboard u can use 80 wire cable for any IDE device.
There is no benefit in doing it for cd/dvd drives as far as I'm aware, but if thats the only spare cable u have then it will work perfectly fine.
All my drives are on 80 wire with no problems what so ever.
Click to expand...

you are correct daveml!!! ;)
 
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V

videobruce

1
though I seem to recall that Ultra devices may be restricted to no more than ATA/33 if there is a non-Ultra device on the same cable - though this may be a myth derived from the 40/80 wire handling!
Click to expand...
That is another question, if you put a CD drive on the same bus as a HDD will that affect the xfer rate of the HDD (slow it down)?
 
L

LTR12101B

1
Two issues on speed, with OLD controllers, two drives ran at the speed of the slowest, but modern DMA mode controllers tend to support split speed working - though Ultra modes may be restricted for reliability/stability reasons if a non-ultra device shares .... I had an ATA/33 and an older (16) device sharing, and it was not very stable until I lowered the Ultra/33 device to 16 as well.

The second issue, I forget where I saw it tested, found that although dissimilar speed devices tend to produce their own fastest speeds used individually - if simultaneous access isw attempted, the slower device appears to drag the faster one down to the same speed (bus occupancy/arbitration problem?)
 
T

Tommy

1
I too have 80 wire cable on udma 33 devices with no problems, there are however CD-ROM drives emerging which are UDMA 66 so I would only us 80 wire on those personally.
 
V

videobruce

1
That seems to make sense. I still see people saying you can't mix devices at all.
Why is there a limit to the number of IDE channels a MB will support without going into another type of Raid type controller (Highpoint or Promise)? Why can't there be IDE 3? Is it a O/S issue or bios issue?
 
L

LTR12101B

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I guess the chipset makers don't deem it neccessary to support more than two IDE channels natively within their chipset.

Tertiary IDE is definitely possible - in the days of CD-ROM interfaces on soundcards, there were soundcard which could provide a 3rd IDE - though the port and IRQ expected were not really standardized.

Way back, you had to have a card for just ONE IDE - and that was ISA bus. With the inegration into chipsets, dual IDE became the norm, and the port and IRQ mapping was pretty well set in stone at that time - It would have been much better if the original PC design had been buried, and a new start made - and if Apple had licenced clones at reasonable prices, we'd all be using Apple compatibles, they would be the leading software house, and Gates would be just another spotty geek.
 
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