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25718e0887
Mode Sense (6) supports a 32-bit number for the maximum block count, where Mode Sense (10) supports a 64-bit number for the count. The Seagate SCSI Commands Reference Manual from 2016, has this to say about a "Short LBA mode parameter block descriptor" as returned by Mode Sense (6): > On a MODE SENSE command, if the number of logical blocks on the > medium exceeds the maximum value that is able to be specified in > the NUMBER OF LOGICAL BLOCKS field, the device server shall return > a value of FFFFFFFh. Similarly, the Read Capacity (10) command should return FFFFFFFFh if the capacity of the drive exceeds 2^32 sectors, and that a driver should then know to use Read Capacity (16) if it supports that command. There may be an unexpected side-effect if presenting a drive of more than 2^32 sectors to a legacy host that does not support devices that large. The Read Capacity commands specify the value returned as the last addressable sector on the device. This means that typically, an application which uses the value returned by that command is going to add 1 to it to get the actual number of blocks on a given device. If the program is not aware of Read Capacity (16), and is not using greater than 32-bit math, then it might report to the user that the total number of sectors on the drive as 0. I don't view this as a huge problem, however. In that case, the legacy driver wouldn't correctly support the capacity of the drive anyway, so providing that driver with a device that is 2 ^ 32 sectors or larger wouldn't make sense from the user perspective.
79 lines
2.2 KiB
C++
79 lines
2.2 KiB
C++
//---------------------------------------------------------------------------
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//
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// X68000 EMULATOR "XM6"
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//
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// Copyright (C) 2001-2006 ＰＩ．(ytanaka@ipc-tokai.or.jp)
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// Copyright (C) 2014-2020 GIMONS
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//
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// XM6i
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// Copyright (C) 2010-2015 isaki@NetBSD.org
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//
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// Imported sava's Anex86/T98Next image and MO format support patch.
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// Comments translated to english by akuker.
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//
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//---------------------------------------------------------------------------
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#pragma once
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#include "generated/piscsi_interface.pb.h"
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#include <span>
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#include <array>
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#include <memory>
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#include <string>
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using namespace std;
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using namespace piscsi_interface;
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class DiskCache
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{
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// Number of tracks to cache
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static const int64_t CACHE_MAX = 16;
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uint64_t read_error_count = 0;
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uint64_t write_error_count = 0;
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uint64_t cache_miss_read_count = 0;
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uint64_t cache_miss_write_count = 0;
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inline static const string READ_ERROR_COUNT = "read_error_count";
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inline static const string WRITE_ERROR_COUNT = "write_error_count";
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inline static const string CACHE_MISS_READ_COUNT = "cache_miss_read_count";
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inline static const string CACHE_MISS_WRITE_COUNT = "cache_miss_write_count";
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public:
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// Internal data definition
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using cache_t = struct {
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shared_ptr<DiskTrack> disktrk; // Disk Track
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uint32_t serial; // Serial
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};
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DiskCache(const string&, int, uint64_t, off_t = 0);
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~DiskCache() = default;
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void SetRawMode(bool b) { cd_raw = b; } // CD-ROM raw mode setting
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bool Save(); // Save and release all
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bool ReadSector(span<uint8_t>, uint64_t); // Sector Read
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bool WriteSector(span<const uint8_t>, uint64_t); // Sector Write
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vector<PbStatistics> GetStatistics(bool) const;
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private:
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// Internal Management
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shared_ptr<DiskTrack> Assign(int64_t);
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shared_ptr<DiskTrack> GetTrack(uint64_t);
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bool Load(int index, int64_t track, shared_ptr<DiskTrack>);
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void UpdateSerialNumber();
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// Internal data
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array<cache_t, CACHE_MAX> cache = {}; // Cache management
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uint32_t serial = 0; // Last serial number
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string sec_path; // Path
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int sec_size; // Sector Size (8=256, 9=512, 10=1024, 11=2048, 12=4096)
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int64_t sec_blocks; // Blocks per sector
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bool cd_raw = false; // CD-ROM RAW mode
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off_t imgoffset; // Offset to actual data
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};
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