commit c0784d9da6780be5b9b33208c5647669b46146df
parent ce8949b748700fca792febfbc7874b44cc3f0225
Author: MikoĊaj Lenczewski <mikolaj@lenczewski.org>
Date: Tue, 9 Jun 2026 19:44:46 +0100
Add some readme notes
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+jbod
+==============================================================================
+Design files for building a 4U, 19-inch, 800mm deep rackmount JBOD chassis.
+
+jbod: Project Layout
+==============================================================================
+Files for the sheet-metal enclosure can be found under the `openscad/`
+subdirectory. These include all the code to turn the openscad script into
+files ready to send for cutting and bending, and which hopefully result in a
+suitable, rack-mountable chassis.
+
+Files for all the PCBs can be found under the `kicad/` subdirectory. These
+include a custom symbol library (e.g. for connectors missing from the standard
+kicad library), the "mainboard" (such as it is), and the drive backplanes.
+These should be ready to be converted to the relevant file formats to be
+sent to be manufactured.
+
+Code, scripts, and other extra resources can be found under the `extra/`
+subdirectory. Code includes some build instructions, scripts should run
+standalone where possible.
+
+jbod: Design Notes
+==============================================================================
+Some notes, in no particular order:
+
+- The chassis is a 4U enclosure for 19-inch racks, and is 800 mm deep
+ + The chassis will support standard 31-inch rack rails
+
+- The chassis front panel will be a dust-filtered mesh, with rack handles
+ + The front panel grille will be a 3D printed design
+ + The dust filter will be an existing stamped part
+ + No drives are accessible via the front panel
+
+- The chassis will have a tool-less top panel
+
+- The chassis has a two-chambered design for separate airflow regions
+ + One chamber is solely for the 3.5-inch disks, with 6x push-pull fans
+ + One chamber is for the PSUs, expanders, and motherboard, with 1x pull fan
+ + Noctua 140mm industrial 2000rpm pwm fans (w/h/l 140/140/25 mm)
+ - https://www.noctua.at/en/products/nf-a14-industrialppc-2000-pwm/specifications
+ + Noctua 120mm industrial 2000rpm pwm fans (w/h/l 120/120/25 mm)
+ - https://www.noctua.at/en/products/nf-f12-industrialppc-2000-pwm/specifications
+ + Noctua 80mm chomax swap pwm fans (w/h/l 80/80/25 mm)
+ - https://www.noctua.at/en/products/nf-a8-pwm-chromax-black-swap#hero
+
+- The chassis has dimensions w/h/l 480/177/800 mm
+ + Front panel dimensions (w/h/l x/y/z mm)
+ + Enclosure dimensions (w/h/l x/y/z mm)
+
+- The chassis supports redundant 1+1 CRPS 1000W+ PSUs
+ + Open Compute M-CRPS form factor standard PSUs (w/h/l 75/40/185+11 mm)
+ - https://www.opencompute.org/documents/m-crps-r1-v1p0-rc4-pdf
+
+- The chassis supports up to 2x SAS4 expanders, with multipath to all disks
+ + The chassis has a 1x4 sff-8674 external port per expander
+ - https://members.snia.org/document/dl/25967
+ + Each expander is connected to each disk for SAS multipath
+
+- The chassis holds 72x 3.5-inch disks in a 6x12 configuration
+ + 3.5-inch disk dimensions (w/h/l 105/30/150 mm)
+ + Drives are in groups of 4, with 4 U.3 connectors per backplane
+ + Backplanes have a single sff-8654 8i U10 connector per backplane
+ - Each drive is connected in a x1 configuration to each expander
+ - Each drive can be connected to up to 2 expanders
+
+- The motherboard supports SMBus, PMBus, UBM, PWM, and a serial console
+ + SMBus controls individual disks
+ + PMBus controls the PSUs
+ + UBM controls the motherboard and disk routing from the host
+ + PWM controls tehe fans
+
+jbod: References
+==============================================================================
+- https://www.aicipc.com/products-detail/j4078-01-35x/
+- https://www.aicipc.com/products-detail/j4108-01-35x/
