{"id":476842,"date":"2023-08-09T09:04:34","date_gmt":"2023-08-09T09:04:34","guid":{"rendered":""},"modified":"2023-09-05T11:13:34","modified_gmt":"2023-09-05T11:13:34","slug":"direct-memory-access","status":"publish","type":"wiki","link":"https:\/\/oneproxy.pro\/jp\/wiki\/direct-memory-access\/","title":{"rendered":"\u30c0\u30a4\u30ec\u30af\u30c8\u30e1\u30e2\u30ea\u30a2\u30af\u30bb\u30b9"},"content":{"rendered":"<h2>\u5c0e\u5165<\/h2>\n<p>\u30c0\u30a4\u30ec\u30af\u30c8 \u30e1\u30e2\u30ea \u30a2\u30af\u30bb\u30b9 (DMA) \u306f\u3001\u30b3\u30f3\u30d4\u30e5\u30fc\u30bf \u30b7\u30b9\u30c6\u30e0\u306e\u5206\u91ce\u3067\u91cd\u8981\u306a\u30c6\u30af\u30ce\u30ed\u30b8\u3067\u3042\u308a\u3001\u4e2d\u592e\u51e6\u7406\u88c5\u7f6e (CPU) \u304c\u76f4\u63a5\u95a2\u4e0e\u3059\u308b\u3053\u3068\u306a\u304f\u3001\u30c7\u30d0\u30a4\u30b9\u3068\u30e1\u30e2\u30ea\u9593\u306e\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u8ee2\u9001\u3092\u53ef\u80fd\u306b\u3057\u307e\u3059\u3002\u3053\u306e\u6a5f\u80fd\u306b\u3088\u308a\u3001\u30c7\u30fc\u30bf\u306e\u79fb\u52d5\u304c\u3088\u308a\u9ad8\u901f\u304b\u3064\u5408\u7406\u5316\u3055\u308c\u308b\u305f\u3081\u3001\u30cd\u30c3\u30c8\u30ef\u30fc\u30af\u3001\u30b9\u30c8\u30ec\u30fc\u30b8\u3001\u30de\u30eb\u30c1\u30e1\u30c7\u30a3\u30a2\u51e6\u7406\u306a\u3069\u306e\u3055\u307e\u3056\u307e\u306a\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306b\u304a\u3044\u3066 DMA \u304c\u4e0d\u53ef\u6b20\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n<h2>\u30c0\u30a4\u30ec\u30af\u30c8 \u30e1\u30e2\u30ea \u30a2\u30af\u30bb\u30b9\u306e\u8d77\u6e90<\/h2>\n<p>\u30c0\u30a4\u30ec\u30af\u30c8 \u30e1\u30e2\u30ea \u30a2\u30af\u30bb\u30b9\u306e\u6982\u5ff5\u306f\u3001\u30a8\u30f3\u30b8\u30cb\u30a2\u304c\u30c7\u30fc\u30bf\u8ee2\u9001\u30bf\u30b9\u30af\u3092 CPU \u304b\u3089\u5c02\u7528\u30cf\u30fc\u30c9\u30a6\u30a7\u30a2\u306b\u30aa\u30d5\u30ed\u30fc\u30c9\u3059\u308b\u65b9\u6cd5\u3092\u6a21\u7d22\u3057\u3066\u3044\u305f\u30b3\u30f3\u30d4\u30e5\u30fc\u30c6\u30a3\u30f3\u30b0\u306e\u521d\u671f\u306b\u521d\u3081\u3066\u767b\u5834\u3057\u307e\u3057\u305f\u3002 \u300cDMA\u300d\u3068\u3044\u3046\u7528\u8a9e\u306f 1960 \u5e74\u4ee3\u306b\u9020\u3089\u308c\u3001\u521d\u671f\u306e\u5b9f\u88c5\u306f\u30df\u30cb\u30b3\u30f3\u30d4\u30e5\u30fc\u30bf\u30fc\u3084\u30e1\u30a4\u30f3\u30d5\u30ec\u30fc\u30e0 \u30b7\u30b9\u30c6\u30e0\u306b\u767b\u5834\u3057\u307e\u3057\u305f\u3002 IBM \u306f\u30011968 \u5e74\u306b\u5c0e\u5165\u3055\u308c\u305f System\/360 Model 85 \u3067 DMA \u306e\u5148\u99c6\u8005\u3068\u3057\u3066\u8a55\u4fa1\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n<h2>\u30c0\u30a4\u30ec\u30af\u30c8 \u30e1\u30e2\u30ea \u30a2\u30af\u30bb\u30b9\u306e\u8a73\u7d30\u60c5\u5831<\/h2>\n<p>DMA \u3092\u4f7f\u7528\u3059\u308b\u3068\u3001\u30cd\u30c3\u30c8\u30ef\u30fc\u30af \u30ab\u30fc\u30c9\u3084\u30c7\u30a3\u30b9\u30af \u30b3\u30f3\u30c8\u30ed\u30fc\u30e9\u306a\u3069\u306e\u30c7\u30d0\u30a4\u30b9\u304c\u3001CPU \u306e\u7d99\u7d9a\u7684\u306a\u4ecb\u5165\u306a\u3057\u306b\u3001\u30b7\u30b9\u30c6\u30e0\u306e\u30e1\u30e2\u30ea\u3068\u306e\u9593\u3067\u30c7\u30fc\u30bf\u3092\u76f4\u63a5\u8ee2\u9001\u3067\u304d\u308b\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002 CPU \u304c\u5404\u30c7\u30fc\u30bf\u8ee2\u9001\u30b9\u30c6\u30c3\u30d7\u306b\u95a2\u4e0e\u3059\u308b\u5f93\u6765\u306e CPU \u5236\u5fa1\u306e I\/O \u306e\u4ee3\u308f\u308a\u306b\u3001DMA \u3092\u4f7f\u7528\u3059\u308b\u3068\u3001\u5468\u8fba\u6a5f\u5668\u3068\u30e1\u30e2\u30ea\u306e\u9593\u3067\u30c7\u30fc\u30bf\u304c\u76f4\u63a5\u6d41\u308c\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n<h2>\u30c0\u30a4\u30ec\u30af\u30c8\u30e1\u30e2\u30ea\u30a2\u30af\u30bb\u30b9\u306e\u5185\u90e8\u69cb\u9020<\/h2>\n<p>DMA \u306e\u4e2d\u5fc3\u306b\u306f\u3001\u30c7\u30d0\u30a4\u30b9\u3068\u30e1\u30e2\u30ea\u9593\u306e\u30c7\u30fc\u30bf\u8ee2\u9001\u3092\u7ba1\u7406\u3059\u308b DMA \u30b3\u30f3\u30c8\u30ed\u30fc\u30e9 (DMA \u30a8\u30f3\u30b8\u30f3\u307e\u305f\u306f DMA \u30b3\u30f3\u30c8\u30ed\u30fc\u30e9 \u30e6\u30cb\u30c3\u30c8\u3068\u3082\u547c\u3070\u308c\u308b) \u304c\u3042\u308a\u307e\u3059\u3002 DMA \u30b3\u30f3\u30c8\u30ed\u30fc\u30e9\u306b\u306f\u3001\u30c7\u30fc\u30bf\u306e\u79fb\u52d5\u3092\u51e6\u7406\u3059\u308b\u305f\u3081\u306e\u72ec\u81ea\u306e\u30ec\u30b8\u30b9\u30bf\u3068\u30ed\u30b8\u30c3\u30af\u306e\u30bb\u30c3\u30c8\u304c\u3042\u308a\u307e\u3059\u3002\u30c7\u30d0\u30a4\u30b9\u304c\u30c7\u30fc\u30bf\u3092\u8ee2\u9001\u3059\u308b\u5fc5\u8981\u304c\u3042\u308b\u5834\u5408\u3001\u30c7\u30d0\u30a4\u30b9\u306f DMA \u30b3\u30f3\u30c8\u30ed\u30fc\u30e9\u306b\u5bfe\u3057\u3066 DMA \u30ea\u30af\u30a8\u30b9\u30c8\u3092\u958b\u59cb\u3057\u3001\u8ee2\u9001\u5143\u3001\u5b9b\u5148\u3001\u304a\u3088\u3073\u8ee2\u9001\u3059\u308b\u30c7\u30fc\u30bf\u91cf\u3092\u6307\u5b9a\u3057\u307e\u3059\u3002<\/p>\n<p>\u4e00\u822c\u7684\u306a DMA \u8ee2\u9001\u306b\u5fc5\u8981\u306a\u624b\u9806\u306f\u6b21\u306e\u3068\u304a\u308a\u3067\u3059\u3002<\/p>\n<ol>\n<li><strong>\u30ea\u30af\u30a8\u30b9\u30c8<\/strong>: \u30c7\u30d0\u30a4\u30b9\u306f DMA \u30ea\u30af\u30a8\u30b9\u30c8\u3092\u958b\u59cb\u3057\u3001\u30c7\u30fc\u30bf\u8ee2\u9001\u306e\u8a73\u7d30\u3092\u793a\u3057\u307e\u3059\u3002<\/li>\n<li><strong>\u4ef2\u88c1<\/strong>: \u8907\u6570\u306e\u30c7\u30d0\u30a4\u30b9\u304c\u540c\u6642\u306b DMA \u3092\u8981\u6c42\u3057\u305f\u5834\u5408\u3001DMA \u30b3\u30f3\u30c8\u30ed\u30fc\u30e9\u306f\u4e8b\u524d\u5b9a\u7fa9\u3055\u308c\u305f\u8abf\u505c\u30b9\u30ad\u30fc\u30e0\u306b\u57fa\u3065\u3044\u3066\u8981\u6c42\u306b\u512a\u5148\u9806\u4f4d\u3092\u4ed8\u3051\u307e\u3059\u3002<\/li>\n<li><strong>\u30d0\u30b9\u306e\u6240\u6709\u6a29<\/strong>: DMA \u30b3\u30f3\u30c8\u30ed\u30fc\u30e9\u306f\u3001CPU \u304b\u3089\u30b7\u30b9\u30c6\u30e0 \u30d0\u30b9\u306e\u4e00\u6642\u7684\u306a\u5236\u5fa1\u3092\u53d6\u5f97\u3057\u307e\u3059\u3002<\/li>\n<li><strong>\u79fb\u884c<\/strong>: DMA \u30b3\u30f3\u30c8\u30ed\u30fc\u30e9\u306f\u3001\u30c7\u30d0\u30a4\u30b9\u3068\u30e1\u30e2\u30ea\u9593\u3067\u30c7\u30fc\u30bf\u3092\u76f4\u63a5\u8ee2\u9001\u3057\u307e\u3059\u3002<\/li>\n<li><strong>\u5b8c\u4e86<\/strong>: \u8ee2\u9001\u304c\u5b8c\u4e86\u3059\u308b\u3068\u3001DMA \u30b3\u30f3\u30c8\u30ed\u30fc\u30e9\u306f\u30c7\u30d0\u30a4\u30b9\u306b\u901a\u77e5\u3057\u3001\u30d0\u30b9\u3092\u89e3\u653e\u3057\u3066 CPU \u306b\u623b\u3057\u307e\u3059\u3002<\/li>\n<\/ol>\n<h2>\u30c0\u30a4\u30ec\u30af\u30c8 \u30e1\u30e2\u30ea \u30a2\u30af\u30bb\u30b9\u306e\u4e3b\u306a\u6a5f\u80fd\u306e\u5206\u6790<\/h2>\n<p>DMA \u306f\u3001DMA \u3092\u4fa1\u5024\u306e\u3042\u308b\u30c6\u30af\u30ce\u30ed\u30b8\u30fc\u306b\u3059\u308b\u3044\u304f\u3064\u304b\u306e\u91cd\u8981\u306a\u6a5f\u80fd\u3092\u63d0\u4f9b\u3057\u307e\u3059\u3002<\/p>\n<ol>\n<li><strong>CPU \u30aa\u30fc\u30d0\u30fc\u30d8\u30c3\u30c9\u306e\u524a\u6e1b<\/strong>: DMA \u306f\u30c7\u30fc\u30bf\u8ee2\u9001\u30bf\u30b9\u30af\u3092 CPU \u304b\u3089\u30aa\u30d5\u30ed\u30fc\u30c9\u3059\u308b\u3053\u3068\u3067\u8cb4\u91cd\u306a\u51e6\u7406\u30ea\u30bd\u30fc\u30b9\u3092\u89e3\u653e\u3057\u3001CPU \u304c\u3088\u308a\u91cd\u8981\u306a\u30bf\u30b9\u30af\u306b\u96c6\u4e2d\u3067\u304d\u308b\u3088\u3046\u306b\u3057\u307e\u3059\u3002<\/li>\n<li><strong>\u3088\u308a\u9ad8\u901f\u306a\u30c7\u30fc\u30bf\u8ee2\u9001<\/strong>: DMA \u306f\u3001\u5f93\u6765\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u3055\u308c\u305f I\/O \u65b9\u5f0f\u3088\u308a\u3082\u9ad8\u901f\u306b\u30c7\u30d0\u30a4\u30b9\u3068\u30e1\u30e2\u30ea\u9593\u3067\u30c7\u30fc\u30bf\u3092\u8ee2\u9001\u3057\u307e\u3059\u3002<\/li>\n<li><strong>\u975e\u540c\u671f\u64cd\u4f5c<\/strong>: DMA \u306f CPU \u3068\u306f\u72ec\u7acb\u3057\u3066\u52d5\u4f5c\u3059\u308b\u305f\u3081\u3001\u30c7\u30d0\u30a4\u30b9\u306f CPU \u306e\u52d5\u4f5c\u3068\u540c\u6642\u306b\u30c7\u30fc\u30bf\u3092\u8ee2\u9001\u3067\u304d\u307e\u3059\u3002<\/li>\n<li><strong>\u5408\u7406\u5316\u3055\u308c\u305f\u30c7\u30fc\u30bf\u79fb\u52d5<\/strong>: DMA \u306b\u3088\u308a\u4e2d\u9593\u30d0\u30c3\u30d5\u30a1\u30ea\u30f3\u30b0\u306e\u5fc5\u8981\u6027\u304c\u306a\u304f\u306a\u308a\u3001\u30ec\u30a4\u30c6\u30f3\u30b7\u304c\u77ed\u7e2e\u3055\u308c\u3001\u30b7\u30b9\u30c6\u30e0\u5168\u4f53\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u304c\u5411\u4e0a\u3057\u307e\u3059\u3002<\/li>\n<\/ol>\n<h2>\u30c0\u30a4\u30ec\u30af\u30c8 \u30e1\u30e2\u30ea \u30a2\u30af\u30bb\u30b9\u306e\u7a2e\u985e<\/h2>\n<p>DMA \u306f\u3001\u30c7\u30fc\u30bf\u8ee2\u9001\u306e\u65b9\u5411\u306b\u57fa\u3065\u3044\u3066\u3001\u4e3b\u306b 3 \u3064\u306e\u30bf\u30a4\u30d7\u306b\u5206\u985e\u3067\u304d\u307e\u3059\u3002<\/p>\n<table>\n<thead>\n<tr>\n<th>\u30bf\u30a4\u30d7<\/th>\n<th>\u8aac\u660e<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>\u5358\u4e00\u306e DMA<\/strong><\/td>\n<td>\u30c7\u30fc\u30bf\u8ee2\u9001\u306f\u30011 \u3064\u306e\u7279\u5b9a\u306e\u30c7\u30d0\u30a4\u30b9\u3068\u30e1\u30e2\u30ea\u306e\u9593\u3067\u884c\u308f\u308c\u307e\u3059\u3002<\/td>\n<\/tr>\n<tr>\n<td><strong>\u30ab\u30b9\u30b1\u30fc\u30c9 DMA<\/strong><\/td>\n<td>\u8907\u6570\u306e DMA \u30b3\u30f3\u30c8\u30ed\u30fc\u30e9\u304c\u30c7\u30a4\u30b8\u30fc\u30c1\u30a7\u30fc\u30f3\u63a5\u7d9a\u3055\u308c\u3001\u30c7\u30d0\u30a4\u30b9\u9593\u306e\u30c7\u30fc\u30bf\u8ee2\u9001\u306e\u30c1\u30a7\u30fc\u30f3\u63a5\u7d9a\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3059\u3002<\/td>\n<\/tr>\n<tr>\n<td><strong>\u8907\u6570\u306e DMA<\/strong><\/td>\n<td>\u8907\u6570\u306e\u30c7\u30d0\u30a4\u30b9\u3068\u30e1\u30e2\u30ea\u9593\u306e\u540c\u6642 DMA \u8ee2\u9001\u3002<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>\u30c0\u30a4\u30ec\u30af\u30c8 \u30e1\u30e2\u30ea \u30a2\u30af\u30bb\u30b9\u306e\u4f7f\u7528\u65b9\u6cd5\u3001\u554f\u984c\u3001\u304a\u3088\u3073\u89e3\u6c7a\u7b56<\/h2>\n<h3>DMA \u306e\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3:<\/h3>\n<ul>\n<li><strong>\u30cd\u30c3\u30c8\u30ef\u30fc\u30ad\u30f3\u30b0<\/strong>: DMA \u306f\u3001\u30cd\u30c3\u30c8\u30ef\u30fc\u30af \u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30a4\u30b9 \u30ab\u30fc\u30c9 (NIC) \u3067\u306e\u9ad8\u901f\u30c7\u30fc\u30bf\u8ee2\u9001\u306b\u4e0d\u53ef\u6b20\u3067\u3042\u308a\u3001\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u306e\u53d7\u4fe1\u3068\u9001\u4fe1\u3092\u53ef\u80fd\u306b\u3057\u307e\u3059\u3002<\/li>\n<li><strong>\u30b9\u30c8\u30ec\u30fc\u30b8<\/strong>: DMA \u306f\u3001CPU \u306e\u4ecb\u5165\u306a\u3057\u306b\u30b9\u30c8\u30ec\u30fc\u30b8 \u30c7\u30d0\u30a4\u30b9\u304b\u3089\u30c7\u30fc\u30bf\u3092\u8aad\u307f\u66f8\u304d\u3059\u308b\u305f\u3081\u306b\u30c7\u30a3\u30b9\u30af \u30b3\u30f3\u30c8\u30ed\u30fc\u30e9\u3067\u4f7f\u7528\u3055\u308c\u307e\u3059\u3002<\/li>\n<li><strong>\u30aa\u30fc\u30c7\u30a3\u30aa\/\u30d3\u30c7\u30aa\u51e6\u7406<\/strong>: DMA \u306f\u3001\u30de\u30eb\u30c1\u30e1\u30c7\u30a3\u30a2 \u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u306e\u30ea\u30a2\u30eb\u30bf\u30a4\u30e0 \u30c7\u30fc\u30bf \u30b9\u30c8\u30ea\u30fc\u30df\u30f3\u30b0\u3092\u4fc3\u9032\u3057\u3001\u30aa\u30fc\u30c7\u30a3\u30aa\u3068\u30d3\u30c7\u30aa\u306e\u9045\u5ef6\u3092\u6700\u5c0f\u9650\u306b\u6291\u3048\u307e\u3059\u3002<\/li>\n<\/ul>\n<h3>\u8ab2\u984c\u3068\u89e3\u6c7a\u7b56:<\/h3>\n<ul>\n<li><strong>\u30c7\u30fc\u30bf\u306e\u4e00\u8cab\u6027<\/strong>: DMA \u8ee2\u9001\u4e2d\u306b CPU \u3068\u30c7\u30d0\u30a4\u30b9\u9593\u306e\u30c7\u30fc\u30bf\u306e\u4e00\u8cab\u6027\u3092\u78ba\u4fdd\u3059\u308b\u3053\u3068\u306f\u56f0\u96e3\u306a\u5834\u5408\u304c\u3042\u308a\u307e\u3059\u3002\u3053\u306e\u554f\u984c\u306b\u5bfe\u51e6\u3059\u308b\u305f\u3081\u306b\u3001\u30ad\u30e3\u30c3\u30b7\u30e5\u7ba1\u7406\u6280\u8853\u3068\u9069\u5207\u306a\u540c\u671f\u30e1\u30ab\u30cb\u30ba\u30e0\u304c\u63a1\u7528\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/li>\n<li><strong>DMA \u306e\u7af6\u5408<\/strong>: \u8907\u6570\u306e\u30c7\u30d0\u30a4\u30b9\u304c\u540c\u6642\u306b DMA \u30a2\u30af\u30bb\u30b9\u3092\u7af6\u5408\u3059\u308b\u3068\u3001\u7af6\u5408\u304c\u767a\u751f\u3059\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002\u7af6\u5408\u3092\u56de\u907f\u3059\u308b\u306b\u306f\u3001\u9069\u5207\u306a\u512a\u5148\u9806\u4f4d\u4ed8\u3051\u3068\u8abf\u505c\u30e1\u30ab\u30cb\u30ba\u30e0\u304c\u4e0d\u53ef\u6b20\u3067\u3059\u3002<\/li>\n<li><strong>\u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u4e0a\u306e\u61f8\u5ff5<\/strong>: DMA \u3078\u306e\u4e0d\u6b63\u30a2\u30af\u30bb\u30b9\u306f\u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u4fb5\u5bb3\u306b\u3064\u306a\u304c\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002\u30b7\u30b9\u30c6\u30e0\u8a2d\u8a08\u8005\u306f\u3001\u3053\u306e\u3088\u3046\u306a\u30ea\u30b9\u30af\u3092\u8efd\u6e1b\u3059\u308b\u305f\u3081\u306b\u3001\u5805\u7262\u306a\u30a2\u30af\u30bb\u30b9\u5236\u5fa1\u30e1\u30ab\u30cb\u30ba\u30e0\u3092\u5b9f\u88c5\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002<\/li>\n<\/ul>\n<h2>\u4e3b\u306a\u7279\u5fb4\u3068\u6bd4\u8f03<\/h2>\n<table>\n<thead>\n<tr>\n<th>\u7279\u6027<\/th>\n<th>DMA<\/th>\n<th>\u30d7\u30ed\u30b0\u30e9\u30e0\u3055\u308c\u305fI\/O<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>CPU \u306e\u95a2\u4e0e<\/strong><\/td>\n<td>\u6700\u5c0f\u9650\u306e\u72ec\u7acb\u3057\u305f\u8ee2\u9001<\/td>\n<td>CPU \u3092\u96c6\u4e2d\u7684\u306b\u4f7f\u7528\u3059\u308b\u30b9\u30c6\u30c3\u30d7\u30d0\u30a4\u30b9\u30c6\u30c3\u30d7\u306e I\/O<\/td>\n<\/tr>\n<tr>\n<td><strong>\u30b9\u30d4\u30fc\u30c9<\/strong><\/td>\n<td>\u3088\u308a\u9ad8\u901f\u306a\u30c7\u30fc\u30bf\u8ee2\u9001<\/td>\n<td>\u30c7\u30fc\u30bf\u8ee2\u9001\u304c\u9045\u3044<\/td>\n<\/tr>\n<tr>\n<td><strong>\u30aa\u30fc\u30d0\u30fc\u30d8\u30c3\u30c9<\/strong><\/td>\n<td>\u4f4e\u3044<\/td>\n<td>\u9ad8\u3044<\/td>\n<\/tr>\n<tr>\n<td><strong>\u30c7\u30fc\u30bf\u306e\u65b9\u5411<\/strong><\/td>\n<td>\u53cc\u65b9\u5411<\/td>\n<td>\u4e00\u65b9\u5411\u6027<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>\u5c55\u671b\u3068\u5c06\u6765\u306e\u30c6\u30af\u30ce\u30ed\u30b8\u30fc<\/h2>\n<p>\u30b3\u30f3\u30d4\u30e5\u30fc\u30c6\u30a3\u30f3\u30b0 \u30c6\u30af\u30ce\u30ed\u30b8\u30fc\u304c\u9032\u5316\u3057\u7d9a\u3051\u308b\u306b\u3064\u308c\u3066\u3001DMA \u306e\u5c06\u6765\u306f\u6709\u671b\u3067\u3059\u3002\u6f5c\u5728\u7684\u306a\u767a\u5c55\u306b\u306f\u6b21\u306e\u3088\u3046\u306a\u3082\u306e\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n<ul>\n<li><strong>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306e\u5411\u4e0a<\/strong>: DMA \u30b3\u30f3\u30c8\u30ed\u30fc\u30e9\u30fc\u3068\u30d0\u30b9 \u30a2\u30fc\u30ad\u30c6\u30af\u30c1\u30e3\u306e\u9032\u6b69\u306b\u3088\u308a\u3001\u30c7\u30fc\u30bf\u8ee2\u9001\u901f\u5ea6\u304c\u3055\u3089\u306b\u9ad8\u901f\u306b\u306a\u308a\u3001\u9045\u5ef6\u304c\u6e1b\u5c11\u3057\u3001\u30b7\u30b9\u30c6\u30e0\u5168\u4f53\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u304c\u5411\u4e0a\u3057\u307e\u3059\u3002<\/li>\n<li><strong>\u30a8\u30cd\u30eb\u30ae\u30fc\u52b9\u7387<\/strong>: DMA \u306f\u3001CPU \u4f7f\u7528\u7387\u3068\u95a2\u9023\u3059\u308b\u96fb\u529b\u6d88\u8cbb\u3092\u524a\u6e1b\u3059\u308b\u3053\u3068\u306b\u3088\u308a\u3001\u30b7\u30b9\u30c6\u30e0\u306e\u30a8\u30cd\u30eb\u30ae\u30fc\u52b9\u7387\u306e\u5411\u4e0a\u306b\u8ca2\u732e\u3057\u307e\u3059\u3002<\/li>\n<li><strong>\u65b0\u8208\u30c6\u30af\u30ce\u30ed\u30b8\u30fc\u3068\u306e\u7d71\u5408<\/strong>\uff1aDMA\u306f\u3001\u30e2\u30ce\u306e\u30a4\u30f3\u30bf\u30fc\u30cd\u30c3\u30c8\uff08IoT\uff09\u3084\u30a8\u30c3\u30b8\u30b3\u30f3\u30d4\u30e5\u30fc\u30c6\u30a3\u30f3\u30b0\u306a\u3069\u306e\u65b0\u8208\u30c6\u30af\u30ce\u30ed\u30b8\u30fc\u3067\u91cd\u8981\u306a\u5f79\u5272\u3092\u679c\u305f\u3057\u3001\u30c7\u30d0\u30a4\u30b9\u9593\u306e\u52b9\u7387\u7684\u306a\u30c7\u30fc\u30bf\u4ea4\u63db\u3092\u53ef\u80fd\u306b\u3059\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\u3002<\/li>\n<\/ul>\n<h2>\u30d7\u30ed\u30ad\u30b7\u30b5\u30fc\u30d0\u30fc\u3068\u30c0\u30a4\u30ec\u30af\u30c8\u30e1\u30e2\u30ea\u30a2\u30af\u30bb\u30b9<\/h2>\n<p>OneProxy \u306a\u3069\u306e\u30d7\u30ed\u30ad\u30b7 \u30b5\u30fc\u30d0\u30fc\u306f\u3001\u5927\u91cf\u306e\u30c7\u30fc\u30bf \u30c8\u30e9\u30d5\u30a3\u30c3\u30af\u3092\u51e6\u7406\u3059\u308b\u3068\u304d\u306b DMA \u306e\u6069\u6075\u3092\u53d7\u3051\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002 DMA \u5bfe\u5fdc\u30d7\u30ed\u30ad\u30b7 \u30b5\u30fc\u30d0\u30fc\u306f\u3001\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u3068\u30a4\u30f3\u30bf\u30fc\u30cd\u30c3\u30c8\u9593\u3067\u30c7\u30fc\u30bf\u3092\u52b9\u7387\u7684\u306b\u8ee2\u9001\u3059\u308b\u3053\u3068\u306b\u3088\u308a\u3001\u5fdc\u7b54\u6642\u9593\u3068\u5168\u4f53\u7684\u306a\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u5927\u5e45\u306b\u5411\u4e0a\u3055\u305b\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002 DMA \u306f\u3001\u30cd\u30c3\u30c8\u30ef\u30fc\u30af\u8ca0\u8377\u304c\u9ad8\u3044\u30b7\u30ca\u30ea\u30aa\u3084\u30de\u30eb\u30c1\u30e1\u30c7\u30a3\u30a2 \u30b3\u30f3\u30c6\u30f3\u30c4\u3092\u63d0\u4f9b\u3059\u308b\u5834\u5408\u306e\u30d7\u30ed\u30ad\u30b7 \u30b5\u30fc\u30d0\u30fc\u306b\u3068\u3063\u3066\u7279\u306b\u6709\u5229\u3067\u3059\u3002<\/p>\n<h2>\u95a2\u9023\u30ea\u30f3\u30af<\/h2>\n<p>\u30c0\u30a4\u30ec\u30af\u30c8 \u30e1\u30e2\u30ea \u30a2\u30af\u30bb\u30b9\u306e\u8a73\u7d30\u306b\u3064\u3044\u3066\u306f\u3001\u6b21\u306e\u30ea\u30bd\u30fc\u30b9\u3092\u53c2\u7167\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n<ul>\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Direct_memory_access\" target=\"_new\" rel=\"noopener nofollow\">\u30a6\u30a3\u30ad\u30da\u30c7\u30a3\u30a2 \u2013 \u30c0\u30a4\u30ec\u30af\u30c8 \u30e1\u30e2\u30ea \u30a2\u30af\u30bb\u30b9<\/a><\/li>\n<li><a href=\"https:\/\/www.techopedia.com\/definition\/27674\/direct-memory-access-dma\" target=\"_new\" rel=\"noopener nofollow\">\u30c6\u30b3\u30da\u30c7\u30a3\u30a2 \u2013 DMA<\/a><\/li>\n<li><a href=\"https:\/\/www.redbooks.ibm.com\/abstracts\/sg244940.html\" target=\"_new\" rel=\"noopener nofollow\">IBM \u30ec\u30c3\u30c9\u30d6\u30c3\u30af \u2013 DMA \u306e\u6982\u5ff5\u3068\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0<\/a><\/li>\n<\/ul>","protected":false},"featured_media":476843,"menu_order":0,"template":"","meta":{"_acf_changed":false,"content-type":"","inline_featured_image":false,"footnotes":""},"class_list":["post-476842","wiki","type-wiki","status-publish","has-post-thumbnail","hentry"],"acf":{"faq_title":"Frequently Asked Questions about <mark>Direct Memory Access (DMA)<\/mark>","faq_items":[{"question":"What is Direct Memory Access (DMA)?","answer":"<p><strong>Direct Memory Access (DMA)<\/strong> is a technology that allows devices to transfer data directly to and from the system's memory without involving the central processing unit (CPU). It enables faster data movement and reduces CPU overhead.<\/p>"},{"question":"How did Direct Memory Access originate?","answer":"<p>DMA's concept was introduced in the early days of computing during the 1960s. IBM's System\/360 Model 85, launched in 1968, is credited with pioneering DMA.<\/p>"},{"question":"How does Direct Memory Access work?","answer":"<p>DMA uses a dedicated DMA controller to manage data transfers between devices and memory. When a device needs to transfer data, it initiates a DMA request to the controller, which handles the data movement independently from the CPU.<\/p>"},{"question":"What are the key features of Direct Memory Access?","answer":"<p>DMA offers several key features, including reduced CPU overhead, faster data transfer, asynchronous operation, and streamlined data movement.<\/p>"},{"question":"What types of Direct Memory Access exist?","answer":"<p>DMA can be categorized into three main types based on data transfer direction: Single DMA (one device to memory), Cascade DMA (multiple controllers daisy-chained), and Multiple DMA (simultaneous transfers between multiple devices and memory).<\/p>"},{"question":"What are some applications of Direct Memory Access?","answer":"<p>DMA is used in networking for high-speed data transfers, storage for efficient disk I\/O, and multimedia processing for real-time audio and video streaming.<\/p>"},{"question":"What challenges are associated with Direct Memory Access?","answer":"<p>DMA may face challenges like data coherency, DMA conflicts, and security concerns. These issues are addressed through cache management, arbitration mechanisms, and robust access control.<\/p>"},{"question":"How does Direct Memory Access compare to Programmed I\/O?","answer":"<p>DMA involves minimal CPU involvement and offers faster data transfer, while Programmed I\/O is CPU-intensive and slower. DMA's overhead is low, whereas Programmed I\/O has higher overhead.<\/p>"},{"question":"What is the future of Direct Memory Access?","answer":"<p>The future of DMA looks promising with enhanced performance, improved energy efficiency, and integration with emerging technologies like IoT and edge computing.<\/p>"},{"question":"How are proxy servers related to Direct Memory Access?","answer":"<p>Proxy servers, such as OneProxy, can benefit from DMA by efficiently handling data traffic and improving overall performance in high-load scenarios or when serving multimedia content.<\/p>"}]},"_links":{"self":[{"href":"https:\/\/oneproxy.pro\/jp\/wp-json\/wp\/v2\/wiki\/476842","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/oneproxy.pro\/jp\/wp-json\/wp\/v2\/wiki"}],"about":[{"href":"https:\/\/oneproxy.pro\/jp\/wp-json\/wp\/v2\/types\/wiki"}],"version-history":[{"count":0,"href":"https:\/\/oneproxy.pro\/jp\/wp-json\/wp\/v2\/wiki\/476842\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/oneproxy.pro\/jp\/wp-json\/wp\/v2\/media\/476843"}],"wp:attachment":[{"href":"https:\/\/oneproxy.pro\/jp\/wp-json\/wp\/v2\/media?parent=476842"}],"curies":[{"name":"\u3046\u30fc\u3093","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}