Chapter
5
Devices and Volumes
To begin reading files from a medium or creating files on a medium, that medium (hereafter
called a device) and the driver which will be used to access it must be registered with the
file system. After that, a volume must be opened on that device (analogous to “mounting”).
This operation will succeed if and only if the device responds and the file system control
structures (for FAT, the Boot Parameter Block or BPB) are located and validated.
In this manual, as in the design of μC/FS, the terms ‘device’ and ‘volume’ have distinct,
non-overlapping meanings. We define a ‘device’ as a single physical or logical entity which
contains a continuous sequence of addressable sectors . An SD/MMC card is a physical
device.
We define a ‘volume’ as a collection of files and directories on a device .
These definitions were selected so that multiple volumes could be opened on a device (as
shown in Figure 5-1) without requiring ambiguous terminology.
ide:0:
ide:1:
partition1
ide:0:
partition1
ide:1a:
partition2
ide:1b:
Device layer
Volume layer
Figure 5-1 Device and volume architecture.
67
相关PDF资料
AD-UCOS3-SPRD PRD LIC UCOS3 RTOS CORE CCES SGL
AD-UCUSBD-SPRD PRD LIC UCUSB DEV CORE CCES SGL
AD637-EVALZ BOARD EVALUATION FOR AD637
AD736-EVALZ BOARD EVALUATION FOR AD736
AD737-EVALZ BOARD EVALUATION FOR AD737
AD8007AKS-EBZ BOARD EVAL FOR AD8007AKS
AD8018ARU-EVAL BOARD EVAL FOR AD8018
AD8034ART-EBZ BOARD EVAL FOR AD8034ART
相关代理商/技术参数
ADuC-H7020 功能描述:开发板和工具包 - ARM HDR BRD FOR ADUC7020 ARM7 RoHS:否 制造商:Arduino 产品:Development Boards 工具用于评估:ATSAM3X8EA-AU 核心:ARM Cortex M3 接口类型:DAC, ICSP, JTAG, UART, USB 工作电源电压:3.3 V
ADuC-IO7020 功能描述:开发板和工具包 - ARM DEV BRD FOR ADUC7020 ARM7 RoHS:否 制造商:Arduino 产品:Development Boards 工具用于评估:ATSAM3X8EA-AU 核心:ARM Cortex M3 接口类型:DAC, ICSP, JTAG, UART, USB 工作电源电压:3.3 V
ADUCM3027BCBZ-R7 功能描述:LOWPWR CORTEXM3W/128KKEMBEDDED F 制造商:analog devices inc. 系列:* 零件状态:在售 标准包装:1,500
ADUCM3027BCBZ-RL 功能描述:LOWPWR CORTEXM3W/128KKEMBEDDED F 制造商:analog devices inc. 系列:* 零件状态:在售 标准包装:5,000
ADUCM3027BCPZ 功能描述:IC MCU 32BIT 128KB FLASH 64LFCSP 制造商:analog devices inc. 系列:ADuCM 包装:托盘 零件状态:在售 核心处理器:ARM? Cortex?-M3 核心尺寸:32-位 速度:26MHz 连接性:I2C,SPI,UART/USART 外设:DMA,POR,PWM,WDT I/O 数:44 程序存储容量:128KB(128K x 8) 程序存储器类型:闪存 EEPROM 容量:- RAM 容量:96K x 8 电压 - 电源(Vcc/Vdd):1.74 V ~ 3.6 V 数据转换器:A/D 8x12b 振荡器类型:内部 工作温度:-40°C ~ 85°C(TA) 封装/外壳:64-WFQFN 裸露焊盘 供应商器件封装:64-LFCSP(9x9) 标准包装:1
ADUCM3027BCPZ-R7 功能描述:IC MCU 32BIT 128KB FLASH 64LFCSP 制造商:analog devices inc. 系列:ADuCM 包装:剪切带(CT) 零件状态:在售 核心处理器:ARM? Cortex?-M3 核心尺寸:32-位 速度:26MHz 连接性:I2C,SPI,UART/USART 外设:DMA,POR,PWM,WDT I/O 数:44 程序存储容量:128KB(128K x 8) 程序存储器类型:闪存 EEPROM 容量:- RAM 容量:96K x 8 电压 - 电源(Vcc/Vdd):1.74 V ~ 3.6 V 数据转换器:A/D 8x12b 振荡器类型:内部 工作温度:-40°C ~ 85°C(TA) 封装/外壳:64-WFQFN 裸露焊盘 供应商器件封装:64-LFCSP(9x9) 标准包装:1
ADUCM3027BCPZ-RL 功能描述:IC MCU 32BIT 128KB FLASH 64LFCSP 制造商:analog devices inc. 系列:ADuCM 包装:带卷(TR) 零件状态:在售 核心处理器:ARM? Cortex?-M3 核心尺寸:32-位 速度:26MHz 连接性:I2C,SPI,UART/USART 外设:DMA,POR,PWM,WDT I/O 数:44 程序存储容量:128KB(128K x 8) 程序存储器类型:闪存 EEPROM 容量:- RAM 容量:96K x 8 电压 - 电源(Vcc/Vdd):1.74 V ~ 3.6 V 数据转换器:A/D 8x12b 振荡器类型:内部 工作温度:-40°C ~ 85°C(TA) 封装/外壳:64-WFQFN 裸露焊盘 供应商器件封装:64-LFCSP(9x9) 标准包装:2,500
ADUCM3029BCBZ-R7 功能描述:LOWPWR CORTEX M3W/256KEMBEDDED F 制造商:analog devices inc. 系列:* 零件状态:在售 标准包装:1,500