TECHNICAL BULLETIN
Date: 15th Dec 2003 (rev 12Jun 06) No 94
Raised by: TC
Distributed to: as required
Soundtracs Digico, unit 10 Silverglade Business Park Chessington Surrey KT9 2QL England
Tel: +44 (0)1372 845600 Fax: +44 (0)1372 845656 email:
D4, D5, DS-3B, DS-00 MIXERS
OPERATION OF “SAFETRACS” AUTOMATIC RECOVERYSOFTWARE
Safetracs is the system developed for the D4 series mixer further developed for DS series and D5. This allows the mixer control computer to be restarted without loss of audio, provided power is not lost. In the event of power loss, when the mixer is re-powered the mixer will start to pass audio within a few seconds, before the main operating system is loaded.
The control PC autoexec file includes a batch file that starts and loads the audio DSP code and last saved audio parameters immediately the computer boots from the hard-drive before Windows® (D4 DS3B) or the EOS (stripped down Windows®) attempts to load.
The parameters used to run the DSP are either those from the last automatic archive file (D4, DS3B) or from special hardware memory (D5, DS-00).
If power is lost, the EOS should not be affected. The system will reboot without scandisk or any such delay. Win 98 systems should also be set to not run scandisk. BUT if the power is lost whilst the system is shutting down and writing to disk, the outcome cannot be predicted (i.e. random errors or not).
Operation of D5, DS00, D1 and above systems
In a proper shut down the mixer writes startup.ses to HDD, so the system knows how it was at that time. The NVRAM continuously (frame by frame) stores engine parameters. When the system boots it reads and deletes this startup file so the mixer remains as it was at switch off. Everytime a session is loaded (and therefore also at a cold start) or a session saved, a duplicate backup session file is written called _session.ses. This is deleted and replaced by startup.ses at a proper shut down.
In DS00 and other post systems the _session.ses is written not at save or load time but is routinely written at a fixed interval set by from the auto-archive time entered on the system options page. The default auto archive rate is 10 minutes, unless changed by the user. This means any failure will recover to within 10 minutes of that point.
It is the last NVRAM that starts the DSP before the rest of the mixer at a cold start.The audio should match the point at which shut down occurred.
In the event of incorrect shut down the system will see the remaining _session.ses. If this is present (even if there a startup.ses as well) it will ask if the operator wants to load from this in a special “last session exited abnormally” i.e. incorrect shut down, window at start up. If the choice says restore session, this _session file is loaded. This then returns the mixer to the last saved condition. If the session is not there, the mixer will start in with default “empty” session.
Cont
TB 94 page 2
If there is no startup file but a _session is present, this will be loaded and the operator will see “recovering last session” not the usual loading “startup session”.
The NVRAM is then read for engine settings (at the last frame the engine was running) and this is fired snapshot-like into backup session just loaded, to bring it up to date. One can choose to reboot the audio at this point also (causing a complete DSP reset and pause in the audio) or completely restart from a default (empty) session.
If power is lost whilst writing to Flashor HDD and an error is caused,Windows may wake up saying (for example) system.drv is missing and reinstall windows. In this case the EOS is damaged beyond simple repair.
It will be noted that if startup.ses or _session.ses are damaged in such a way they cause a software error, the system will always fail at startup. This is not the same as a damaged Windows installation. See below
In the event of suspected damaged Windows installation, and if the mixer is fitted with a dual drive system, change the boot order in BIOS (use F2 (not delete) to access this) and start over with the other drive. What software is in running on the second drive is at the choice of the owner/operator and detailed in TN 140.
It will noted from above that in the event of a PC failure (so called “crash”) e.g Windows “blue screen” if the PC is reset WITHOUT turning off power, the system will not loose audio and can be restarted. The PC can restarted by a ctl-alt-del (DS00 etc.) or via the hardware reset button (D5, D1 etc.).
In most cases there will be no loss of audio and the control system will restart and return to nearly the previous state, typically the set up last saved by the operator.
Note if the PC is reset, the system should have a power off restart as soon as possible.
Restart direct to Windows bypassing the mixer program
Cold start the mixer and as the bios appears repeated tap the ”shift” key only. This will bypass the windows autoexec and start in the windows desktop directly, without attempting to run the mixer and load a possibly faulty file. Timing is a critical here. If it does not start in desk top try again, tapping the key longer and earlier.
Go to explorer, delete c:\d5\startup.ses also c:\d5\_session.ses (if this exists). (or C:\DS00\startup.ses or appropriate)
This feature is available on all Windows 98 and Windows Me based systems, not early DPC on Windows 311.
D4 and DS3B Operation
Note D4 and DS3B does not use the NVRAM hardware and the DSP is started from the last _session.ses. Therefore audio may not match exactly the audio at shut down, but will match the _session.ses.
_session.ses is written not at save or load time but is routinely written at a fixed interval set by from the auto-archive time entered on the system options page. The default auto archive rate is 10 minutes, unless changed by the user. This means any failure will recover to within 10 minutes of that point.
In most cases there will be no loss of audio and the control system will restart and return to the saved audio state of the _session.ses unless the power is lost.
D4 mixers shipped after Jan 2006 use the same NVRAM card and operate as the DS00 described above
Cont
TB 94 page 3
DPC and DS3 Operation
DPC and DS3 running V3 software (ONLY) is the same as D4, DS3B operation noted above, otherwise only the _session function as described operates without audio recovery prior to loading the session.
TN103.doc\