Here are some thoughts:
- Mainboard should be Mini-ITX to fit into the Kronos
- CPU must support at least the Intel Atom instruction set (Kronos binaries are optimized for Atom)
There is no point in having more than 4 GB RAM since OA.ko and the other proprietary kernel modules are 32 Bit only.Update: 8 GB RAM will allow the kernel and userspace applications to live in high memory while OA can use almost all of the low memory. This will squeeze out 200-300 extra MBs of sample memory.
- There is no point in having more than 2 CPU cores since the signal processing chain is optimized for 2 cores. Each CPU core should be as fast as possible to archive maximum signal processing performance.
- Hardware needs at least one USB port to connect the NKS4 module (probably not hard).
- Hardware needs a RS232 port to connect the Keybed, should be 16550 compatible (might be problematic, because most modern mainboards have no serial ports anymore)
Here is what I came up with:
- Mainboard: Supermicro X11SSV-Q (Mini-ITX, has 2 serial ports - nice!)
- CPU: 6th Generation Core i3-6320 (2 Cores, each with almost 4 GHz - comparison with the CPU inside the Kronos X)
- 8 GB DDR3 Memory
- A fast SSD (adjust size to personal taste)
Obstacles to overcome (updated again):
Skylake chipsets are XHCI only. XHCI-Driver in Kernel 2.6.32 does not support isochronous transfers.Solved by backporting a newer XHCI-Driver. Memory map is not continuous. There are holes for ACPI NVS. Problematic with KORG's way of allocating the synthesizer's heap in ioremapped memory.Solved by setting TOLUD (Top Of Low Usable DRAM) in BIOS settings to 3.5 GB. ACPI stuff is then out of the way. SuperIO-Driver embedded in OA.ko for serial port doesn't work (no keybed yet).Works with the latest OA.ko versions since SuperIO-Chip in Kronos 2 is similar to the one on the X11SSV-Q. Connection cable inside Kronos needs some soldering since the supermicro board has a SUB-D connector and no pin-header for RS232. Kernel 2.6.32 does not support the ethernet MACs on the SX11SSV-Q. Not a real problem since the mainboard's ethernet connection is unused in the original Kronos design. Backporting a driver from a newer kernel should be possible.Intel provides drivers for both NICs that compile as modules against 2.6.32-11. Get prebuilt modules here.
- Kronos boot time < 20s
- 200 voice polyphony accross all engines (even STR-1 and MS-20).
- Total cost: ~ $520