4 x 896 HD on the same FW bus (message from : edwardb)

[cyril]

.

Cyril it is obvious to me that you have not read the Motu 896hd user manual (For Windows). ......

In the case of the pci based motu 424 system, if you say it works for you that's great....I want the 896HD, and i want it to work....besides who am i going to give it back to....

A FW 400 bus allow to have 400 Mbit/s, this is not much at 96 Khz

You may be able to connect 4 x 896 HD but not having the to work at the same time !
Do a trial at 44.1 khz

I told you before a lot of users are having problem with one FW audio and a FW disk on the same FW buss and there solution was to buy and extra FW card to connect there FW disk

Give them back to the shop where you bought them, say ; it does not work or do a trial with an extra FW card !

I was trying to help you !

Best

Cyril

[qo]

A FW 400 bus allow to have 400 Mbit/s, this is not much at 96 Khz

Hmm. Well:

96000 * 24bits = 2,340,000 bits/sec.

400,000,000 / 2,340,000 = 170 tracks.

Each 896HD supports 8 analog in/outs. 4*8 = 32 tracks. Should work, no? Not sure if FW is full-duplex, but even it it isn't, then we're talking about 4*8*2 = 64 tracks max bandwidth (for analog), so 149,760,000 bits/sec for input/output. Which is well within 400Mb/s range.

[edwardb]

Cyril.......sorry, i misunderstood what you were saying, i apologize for that response.....The original thread i posted "Motu Update Your Firmware And Windows XP Drivers" was meant to wake up MOTU because i know they read this forum. It seems to have turned in to a shouting match amongst unicornation members, which was not my intention. I have posted threads here before and got response from motu techs, but they have vanished somehow since my original thread was started.......
I still encourage all the motu xp users with problems to voice their opinions and findings regardless if they are in agreement with me or not...

[cyril]

Not sure if FW is full-duplex.

why does one 896 or other FW audio interfaces and 1 FW disk on the same bus does not work ?

I dont know what is exactly done but there is a problem with FW !

This problem is not only on PC but is also on MAC

What is strange too is the Apple does not support a configuration where you boot from a FW disk ! strange !

Best
`
Cyril

[mothra]

Funny Ive had an 828MKII since the day they came out, after selling the original 828.. Been running with a Lacie d2 160GB FW hard disk I bought the same day..

Never had a problem with it on my mac.. Either when running it on seperate ports at home on my tower, or on my laptop which I now use for studio work.. Which on one lonely port, has my 828MKII->Lacie d2 HD->Lacie d2 DVD-RW. I just finished tracking 6 songs worth of guitar and bass tracks last night, only trouble was me smoking too much and playing sloppy heh..

What are you talking about Apple doesnt support a configuration that boots from a FW hard disk? I can boot any of my macs off my old iPod even (which has OS X installed on it..)

Apple doesnt support booting from a USB disk..
But OS X can boot off of any firewire harddrive you throw at it.

Best to do some research before claiming that things flat out dont work..
They maybe somewhat widespread the issues youre having, but theyre also isolated incidents.. Theres two other studios in our same building that are actually running PC's w/Cubase and 896HDs... They seem to be getting tons of work done and actually paying their rent every month with em..

[cyril]

What are you talking about Apple doesnt support a configuration that boots from a FW hard disk? I can boot any of my macs off my old iPod even (which has OS X installed on it..)

I know you can boot on almost any devices

I Had many problem with my G5 2x2, I was booting from a FW 800 LACIE, I made a RAID 0 with the 2 internal SATA to put my QLSO platinum lib and I had my song files on another FW800 lacie.


The answer from Apple FRANCE was. "NO SPPORT IF YOU BOOT FROM A FW DISK OR FROM A RAID"
You are supported only if you boot from a defined configuration in there catalog !!!!
Asking them why ; the answer was -> FW not reliable enough !

Now I boot from the internal HD an I have an external RAID 0 to put my QLSO - no more MAC OS problems !

FW is great for making backup of your work but is not made for intensive I/O

> Funny Ive had an 828MKII since the day they came out, after selling the original 828.. Been running with a Lacie d2 160GB FW hard disk I bought the same day..

it depends what you have on your FW disk !
If you have big libs (QLSO...) that demands a lot of reading you are in trouble !
See the number of persons that are complaining on Apple/logic web !!

also the 896 HD is 192 khz

[Jidis]

I have posted threads here before and got response from motu techs, but they have vanished somehow

Edward- Man, that's weird. I was wondering about that a while back. How long ago was it, and how often were they here?

Thanks! (and sorry to change the subject)

George

[john jeffers]

Josh Hetrick from MOTU posts as "TechSupport", and he just posted in this thread last Friday, so it hasn't been that long.

[edwardb]

I would like to invite Josh Hetrick to join this thread and shed some light on this discussion.....

[qo]

I did a bit more reading and, yes, FW400 is full duplex (400Mb/s each direction).

why does one 896 or other FW audio interfaces and 1 FW disk on the same bus does not work ?

I dont know what is exactly done but there is a problem with FW !

A disk's I/O will be bursty (max burst being the dependent on the drive's specs). It's asynchronous. Realtime audio I/O is not bursty, it's more deterministic and benefits from an isochronous transport since you don't have to buffer as much and so latency is reduced.

The "traffic" patterns between these two are not very compatible. FW does support isochronous*** transport, but I'm not sure how this is implemented, or even whether it's implemented by Apple or MOTU.

Let's say, hypothetically, that connecting an isochronous device (let's assume a MOTU FW interface is isochronous, though it could very well not be) and an asynchronous device (hard drive) to a FW causes the FW to revert to the lowest common denominator service level (asynchronous). That would definitely impact audio. Again, I'm not sure if this happens since I have no clue about FW specs/implementations. This would be sort of like USB 2.0 reverting to 1.1 speed if any 1.1 devices are connected.

I've heard that FW supports QoS (quality of service), but am guessing that this entails some signalling between the host and the device to allocate/deallocate bandwidth, and also to specify whether you are sending in a packet mode (asynchronous) or a byte-synced mode (isochronous). All this seems a bit much to expect from cheap consumer FW products but, again, I have no clue. I'd love to hear from someone that has more knowledge about FW's internals since I'm really curious about this, and it would be nice to come up with some FW best practices.


*** A definition of "isochronous."

The ISOCHRONOUS (ISOC) format for data transmission is a procedure or protocol in which each information CHARACTER or BYTE is individually synchronized or FRAMED by the use of Start and Stop Elements, also referred to as START BITS and STOP BITS.

Also, Wikopedia's definition for isochronous and asynchronous