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ram/swapfile memory error correction

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### https://gitlab.com/mentalcare/things-i-dont-want-to-forget/issues/1
^^
xcheck @xcheck commented 
Owner

//case study | 26:6//

    USB (USB 2.0) On-The-Go > USB Attached SCSI > … :chains: ~ 2015-01-155/ct/hotline
    micro:bit @ 16MHz core (32-bit) ARM Cortex-M0 w/ RAM: 16KB, flash: 256KB ~ 2017-04-066/ct.de/yygg
    Pi Zero W @ 1GHz core (32-bit) ARMv6Z w/ RAM: 512MB, flash: µSDHC
    Pi Compute Module 3 lite @ 1.2GHz quad-core (64/32-bit) ARMv8-A w/ RAM: 1GB, flash: µSDHC

    Bluetooth 3.0 + HS supports - 24Mbit/s]

    GPIO RAM MODULE ‥ SPI ‥
    https://www.raspberrypi.org/forums/viewtopic.php?f=45&t=114326 … :chains: [¹]
    https://www.raspberrypi.org/documentation/hardware/raspberrypi/spi/README.md … :chains: [²]

—
∵quote ↹ [¹]

    F-RAM is as fast as D-RAM and/or S-RAM, however the I2C devices are limited to a 1Mbit/second transfer rate, with the SPI devices maxing out at 32Mbit/second transfer. However, the SPI controller on the RasPi can only be programmed to go at 24Mbit/second because of the divisor method used internally.

∴etouq ☛ points to SPI @ 24Mbit/s on RasPi (see LPC @ 33MHz speed)

—
∵quote ↹ [²]

    Bidirectional or "3-wire" mode is supported by the spi-bcm2835 kernel module.

    (‥) The SPI Controller driver spi_bcm2708 support speeds in doubles from ~8kHz to ~125MHz.

      cdiv    speed
      2   125.0 MHz

∴etouq ☛ results in ##Mbit/s
^^
xcheck @xcheck commented 
Owner

buzzwords: swapfile,virtual ram,raspi,sbc,usb,sdhc,spi,volatile memory,dram

»DRAM microSD Card«

    1:1 cache overlay ignoring flash errors ]16GB; 32GB] – implying fs setup each reboot
    flash and (hard structured) dram section – saying the flash section shows common behaviour and may be freely partioned
    sdhc hub for a) flash disk and b) volatile disk – speed tradeoff if feasible
    programmable sdhc card – sort of sbc coming with…

USB 2.0 supports - 35MB/s]
SDHC (SD 2.0) supports - 25MB/s]
^^
Volatile µSD Card w/ DRAM -- RasPi

specs: Volatile µSD Card w/ DRAM -- RasPi

(#) msdos partion table

    none volatile odd
    [Ⓐ] partition 8 on flash // type vfat for boot
    [Ⓑ] partition 8 on flash // type ext4|ntfs for f2fs
    volatile left
    [ⓐ] partition 8 on dram // type f2fs for tmpfs
^^

~~~~~~~~ ⌨ 2017-06-17 LUG-Stammtisch droppings ~~~~~~~~
⛱ Android basics ‥ transferred and mirrored diagonal wise
w/ ramdisk rather than eMMC flash


		I/O			PWR / PSU apart						RAM	flash
RasPi 3		4xUSB 2 Standard-A	w/ Y cable USB 2 Micro-B [opt. @5V⁄2.5A ‥biz level]*?!	1GB	µSDHC
RasPi Zero W	USB 2 Micro-B		w/ Y cable USB 2 Micro-B [opt. @5V⁄1A ‥biz level]	512MB	µSDHC
micro:bit	USB 2 Micro-B		JST connector [opt. @3V⁄?A ‥2xAAA Battery]		16KB	256KB


USB 2.0 null modem @35MB/s	swapfile iSCSI passthrough	graduate OS: p2p, client
				USB storage SBC emulated	embedded hackware
				USB Lan adapter


programming ‥ Python
BrandMarks

    program (!¡) an Android Tablet app to handover a ramdisk and pop up a cycling display chart
    implement (!¡) prev pronounced app straight into a certain graduate OS of choice
    extract (!¡) required core functions to map pictured microcontroller firmware last distinct
    design (!¡) blueprint to burn amounts of custom E²PROM and share them …before you reach point 5

draft work to be dated ♋

*?! 2017-07-30 :ok: RasPi3 (w/ SSD) powered from RasPiZeroW via y cable
RasPiZeroW, RasPi3 both Cypress CYW43438 wireless chip

    1GHz, single-core CPU BCM2835
    512MB RAM
    Mini-HDMI port
    Micro-USB On-The-Go port
    Micro-USB power
    HAT-compatible 40-pin header
    Composite video and reset headers
    CSI camera connector
    802.11n wireless LAN
    Bluetooth 4.0