DJ Matías
Collector, connoisseur and DJ of Argentine tango music
Computer system
Three different computer systems with three different operating systems are employed in order to cover the major computing platforms and applications for audio processing and DJ performance:
- MacBook Pro (Apple 17” model with i7 core, OS 10.9 “Mavericks”);
- Tecra M-Series (Toshiba business notebook, Windows 7 “Enterprise” SP 1);
- Nexus 7 (Google/Asus tabloid, Android 4.4 “KitKat”) as backup device.
A stable and reliable computer system is of paramount importance for a professional working DJ. Thus, a lot of effort is dedicated:
- to optimize computer performance;
- to maintain a well-organized system;
- to ensure data integrity and compatibility.
Generally, a new and customized installation of the Microsoft Windows operating system is indispensable in order to obtain a smoothly running system without superfluous and potentially interfering soft- and crapware. The Apple and the Google operating systems, however, can be used just out-of-the box without excessive tuning and further optimization. In any case, it is strongly recommended to minimize the computational load during public DJ performance by turning off any WLAN (Wireless Local Area Network) drivers or Bluetooth devices.
Processing of streaming data in real-time is a challenging task for Windows-based applications and device drivers. This is because by design Windows is not an RTOS (Real-Time Operating System). There is no guarantee that certain actions can be executed in a timely manner. That is not a problem for most devices and tasks but this is bad news for audio streaming applications (which are considered soft real-time) because they need to deliver data to the hardware in buffers several times per second. If one or more buffers miss their deadlines and are not delivered in time, it has audible consequences which are recognized as drop-outs, clicks and pops.
The DPC Latency Checker program is employed
- to analyze the capabilities of the Windows system to handle data streams properly and
- to detect the cause for interruptions in real-time audio applications.
Excessive DPC (Deferred Procedure Call) latencies may be caused if any kernel-mode device driver is implemented improperly. The tool determines and graphically displays the maximum DPC latency that occurs on the Windows system independently of any external hardware.
To identify the processes responsible for causing audio latencies, the LatencyMon software examines possible causes of buffer underruns by measuring kernel timer latencies. A detailed report is provided:
- to display the highest latencies of a kernel timer;
- to report the execution times of DPC and ISR (Interrupt Service Routine) processes;
- to document hard page faults.
In most cases, the LatencyMon tool allows the identification of the routines and drivers responsible for causing audio drop-outs.
Different strategies are employed to back up the music collection and user data on external mass storage devices:
- For the Windows system, the WD (Western Digital) SmartWare automatic backup software is used to continuously store new or modified files instantly on the connected WD My Passport hard drive. The WD Security utility enables password protection and hardware encryption in order to prevent unauthorized use or access.
- The data on the MacBook Pro are continuously backed up using the Time Machine application in OS X. An AirPort Time Capsule provides automatic and wireless data transfer and storage.
- Finally, the music collection and user settings on the Nexus 7 tabloid are backed up in the Google Cloud.