{
  "schema_version": 1,
  "machine": "PEL Impuls 9010 / Orao 64",
  "reconstruction_version": "0.1",
  "reviewed_on": "2026-10-13",
  "conclusion": "An Apple II+ compatibility experiment is supportable. Authentic Impuls firmware and complete hardware emulation are not established by the available evidence.",
  "evidence_method": "All three supplied notes were read. The June 1986 p50, September 1986 pp16-17 and March 1987 p14 scans, and the linked surviving-machine photographs, were independently retrieved and visually inspected. Apple comparison uses Apple's 1979 Reference Manual OCR. Magazine and photo binaries are retained outside the website under orao-tests/impuls-evidence/; only citations and hashes are exposed here.",
  "supplied_sources": [
    {
      "id": "supplied-supplement",
      "original_name": "Orao 64 _ PEL Impuls 9010 — dopuna istraživanja časopisa 1986.–1987_",
      "preserved_file": "supplied/research-supplement-1986-1987.md",
      "sha256": "1dd4d9b9ead4f365ca0027e30377a43f7a6ca9c166e7e6b12488de539d73fba5",
      "bytes": 7341,
      "status": "latest_supplied_research",
      "limitation": "Its unidentified-CRT statement is narrowed by the direct HD6845SP photograph observation below. Its linked detailed-findings companion was not supplied."
    },
    {
      "id": "supplied-confirmed",
      "original_name": "Orao 64 _ PEL Impuls 9010 — potvrđeni nalazi i stanje ROM-a.md",
      "preserved_file": "supplied/confirmed-findings-rom-status.md",
      "sha256": "e99986ca943083beb0be76d5f294bd71a142b7458cea46f5bce851b1766ceb5e",
      "bytes": 5837,
      "status": "supporting_supplied_research"
    },
    {
      "id": "supplied-old-rom",
      "original_name": "ROM i kompatibilnost.md",
      "preserved_file": "supplied/superseded-rom-and-compatibility.md",
      "sha256": "a8462c880b8b7d28d309b427fe4685373cf3a95bf85b1e1b9188de35da3bd762",
      "bytes": 4544,
      "status": "superseded_historical_evidence",
      "invalidated_claim": "Its recommendation of BAS103.ROM and CRT103.ROM as likely Orao 64 replacements is superseded by the two later notes. They belong to the original Orao 103 platform and are not Impuls 9010 firmware."
    }
  ],
  "primary_sources": [
    {
      "id": "sk-1986-06-p50",
      "title": "Svet kompjutera, June 1986, p50: Moćni Orao 64 / Impuls 9010 na sajmu",
      "url": "https://retrospec.elite.org/pcsux/SK/1986/06/Strana-50.jpg",
      "sha256": "6ba036b9f84d491da785fe39b7b700deae4a67caf6036cb4a1da0bff48ff6479",
      "verification": "direct_visual_scan"
    },
    {
      "id": "sk-1986-09-p16",
      "title": "Tihomir Stančević, Impuls 9010 (Orao 64), Svet kompjutera, September 1986, p16",
      "url": "https://retrospec.elite.org/pcsux/SK/1986/09/SEPT8616.jpg",
      "sha256": "d403d2295ec2ac7410b4ba2ce09df0e1a57f4472313e553f47cac9944ffd9f71",
      "verification": "direct_visual_scan"
    },
    {
      "id": "sk-1986-09-p17",
      "title": "Tihomir Stančević, Impuls 9010 (Orao 64), Svet kompjutera, September 1986, p17",
      "url": "https://retrospec.elite.org/pcsux/SK/1986/09/SEPT8617.jpg",
      "sha256": "6ca02f6f0a91eec09029b88df623ddccd3b62a3d697a4f32d993eda229dc57e6",
      "verification": "direct_visual_scan"
    },
    {
      "id": "sk-1987-03-p14",
      "title": "Tihomir Stančević, Bio je show, Svet kompjutera, March 1987, p14",
      "url": "https://retrospec.elite.org/pcsux/SK/1987/03/SK_87_03_014.jpg",
      "sha256": "872b435fac190268fba5a39f4c575a98350d52d626eaeb3506aaee6b57f88e2c",
      "verification": "direct_visual_scan"
    },
    {
      "id": "retroinfo-specimen",
      "title": "RetroInfo: Prototip PEL Impuls 9010 (Orao 64)",
      "url": "https://retroinfo.hr/prototip-pel-impuls-9010-orao-64/",
      "verification": "page_and_linked_photographs"
    },
    {
      "id": "retroinfo-rom-crt",
      "title": "RetroInfo IMG_3198: EPROM and CRT-controller close-up",
      "url": "https://retroinfo.hr/wp-content/uploads/2018/08/IMG_3198.jpg",
      "sha256": "1ee95d66a07cd910b2a4eba90820f1b6f296a42993c18c7a5ba4e987f975447d",
      "verification": "direct_visual_photo"
    },
    {
      "id": "retroinfo-board-revision",
      "title": "RetroInfo IMG_3184: motherboard revision label",
      "url": "https://retroinfo.hr/wp-content/uploads/2018/08/IMG_3184.jpg",
      "sha256": "0c57f351bb9d63f81b8938f51433f7bdb2bb048e597cb2892dc0cf483ba577f4",
      "verification": "direct_visual_photo"
    },
    {
      "id": "retroinfo-local-keyboard",
      "title": "RetroInfo IMG_3191: keyboard with local characters",
      "url": "https://retroinfo.hr/wp-content/uploads/2018/08/IMG_3191.jpg",
      "sha256": "a0778ac70875b6598e4c6bd0ebb6f532343f408c7672e6575d52b70ae990a2e5",
      "verification": "direct_visual_photo"
    },
    {
      "id": "apple-reference-1979",
      "title": "Apple Computer, Apple II Reference Manual, Christopher Espinosa, 1979",
      "url": "https://archive.org/details/apple-ii-ref-manual",
      "text_url": "https://archive.org/stream/apple-ii-ref-manual/Image072217171023.duplex.merged_djvu.txt",
      "verification": "primary_manual_ocr",
      "relevant_printed_pages": [3, 14, 17, 19, 27, 68, 72, 90]
    }
  ],
  "established_facts": [
    {"id": "identity", "fact": "The contemporary test identifies Impuls 9010 as Orao 64, made by PEL Varaždin.", "sources": ["sk-1986-09-p16"]},
    {"id": "cpu", "fact": "The printed configuration uses a 6502A at 2 MHz; additional 65C02 or 65C816 support was described as an option/future development.", "sources": ["sk-1986-09-p17"]},
    {"id": "memory-capacities", "fact": "64 KiB RAM, expansion described as 256 KiB, and 32 KiB ROM are specified.", "sources": ["sk-1986-09-p17", "sk-1986-06-p50"]},
    {"id": "rom-packages", "fact": "Two 16-KiB EPROMs are specified. The photographed specimen has two devices marked HN4827128G-25.", "sources": ["sk-1986-06-p50", "retroinfo-rom-crt"]},
    {"id": "software", "fact": "The ROM environment is described as BOS/SM, BASIC, DOS and monitor; the June report identifies a 12-KiB BASIC.", "sources": ["sk-1986-09-p17", "sk-1986-06-p50"]},
    {"id": "native-display", "fact": "80 columns by 25 rows and 640 by 200 monochrome graphics are specified. The basic bitmap occupies 16 KiB.", "sources": ["sk-1986-09-p16", "sk-1986-09-p17"]},
    {"id": "color-display", "fact": "An optional card is described as 640 by 400 pixels, eight colors per pixel, with three switchable 32-KiB video-memory banks (96 KiB total).", "sources": ["sk-1986-09-p17"]},
    {"id": "address-decoder", "fact": "A programmable address decoder controls overlapping memory. The article describes stable RAM addresses $0000-$BFFF for normal programs and a PAD area $E000-$EFFF used to remap system addresses, including for other 6502 machines such as Apple II.", "sources": ["sk-1986-09-p17"]},
    {"id": "apple-claim", "fact": "The March 1987 report identifies the PEL exhibit as Impuls 9010 (Apple II+). This verifies a contemporary compatibility claim, not a measured compatibility level.", "sources": ["sk-1987-03-p14"]},
    {"id": "local-keyboard", "fact": "The September technical box specifies YUASCII. The photographed keyboard carries Š, Đ, Č, Ć and Ž keycaps.", "sources": ["sk-1986-09-p17", "retroinfo-local-keyboard"]},
    {"id": "specimen-crt", "fact": "The surviving specimen photograph shows a CRT controller marked HD6845SP. Its memory-mapped register addresses and wiring are not visible as a complete circuit specification.", "sources": ["retroinfo-rom-crt"]},
    {"id": "specimen-revision", "fact": "The motherboard photograph bears IMPULS 9010 V1.1. 86 03 03.", "sources": ["retroinfo-board-revision"]},
    {"id": "orao32-incompatibility", "fact": "The June report describes incompatible Orao/Impuls machine code because screen format and system-routine addresses differ.", "sources": ["sk-1986-06-p50"]}
  ],
  "hypotheses": [
    {"id": "apple-compatibility-mode", "claim": "A selectable Apple II+ reference profile is a useful experimental approximation of the reported compatibility.", "status": "explicit_experimental_model", "does_not_establish": "PEL ROM content, PEL bus equivalence, or compatibility of all Apple II+ software."},
    {"id": "national-character-implementation", "claim": "A conventional YUASCII-style character option can demonstrate the documented local-letter support.", "status": "provisional_mapping_and_modern_glyphs", "does_not_establish": "Original code-point assignment, ALT behavior, keyboard scan codes, or bit-identical glyphs."},
    {"id": "experimental-expansion", "claim": "A 256-KiB selectable capacity can be modeled with explicitly experimental banking.", "status": "capacity_documented_bank_protocol_unverified", "does_not_establish": "PEL decoder register assignments or Apple expansion-card compatibility."},
    {"id": "native-video-preview", "claim": "A raster preview can use the documented native dimensions and eight-color capacity.", "status": "display_contract_demonstration", "does_not_establish": "Verified memory layout, CRT timing, color planes, palette, or color-card hardware."}
  ],
  "unknowns": [
    "Authentic Impuls 9010 ROM bytes, checksums, revision and reset/interrupt vectors.",
    "Complete BOS/SM bank-selection mechanism, I/O registers, programmable-decoder truth table and expansion-RAM map.",
    "HD6845SP CPU-visible register addresses, crystal/divider timing, bitmap addressing, font storage and PEL-specific video wiring.",
    "Native color-card palette, plane organization, interlace and switching semantics.",
    "Exact YUASCII code points, lower-case behavior, ALT character set and original glyph bitmaps.",
    "How Apple II+ screen-memory and I/O behavior were mapped to the higher-resolution PEL hardware.",
    "Actual completeness of Apple II+ compatibility and the status of disk/cassette protocols.",
    "The 512 by 256 mode mentioned as personal recollection in the supplied note; not established by the inspected printed specifications.",
    "Number of produced machines and whether all exhibited/prototype revisions share these properties."
  ],
  "apple_reference_comparison": {
    "source": "apple-reference-1979",
    "apple_ii_plus": {"clock_hz": 1023000, "text": [40, 24], "lores": [40, 48], "lores_colors": 16, "hires": [280, 192], "hires_colors": 6, "mainboard_ram_max_bytes": 49152, "language_card_ram_total_bytes": 65536, "system_rom_bytes": 12288},
    "interpretation": "Apple II+ native video and ROM size differ from the documented Impuls configuration. Its 64 KiB physical RAM consists of 48 KiB motherboard RAM and a 16-KiB language card, with two 4-KiB banks sharing $D000-$DFFF; it is not a contiguous simultaneously visible 64-KiB RAM block. This is not evidence of PEL bank organization. Upscaling Apple pixels does not reproduce PEL native video; Apple ROM is reference firmware and must not be labeled as an authentic Impuls dump."
  },
  "implementation_audit": {
    "reviewed_version": "0.1.0",
    "reference_cpu": "NMOS 6502",
    "reference_ram": "48 KiB motherboard RAM plus 16 KiB banked Apple language-card RAM",
    "reference_disk": "Apple Disk II slot 6; not a recovered PEL controller",
    "expansion_selection": "192 KiB additional diagnostic storage at 256-KiB selection; not CPU-mapped",
    "separate_pel_lab": "One or four 64-KiB diagnostic banks, selected in the UI. Native-size test raster with assumed planar color layout; not PEL code execution.",
    "croatian_rendering": "Five hand-drawn uppercase glyph substitutions (Č Ć Ž Š Đ); hypothetical YUASCII-style positions, original firmware unchanged",
    "provenance_file": "../engine/PROVENANCE.json",
    "scope": "Audits current representation and wording, not historical hardware equivalence."
  },
  "reconstruction_boundaries": {
    "authentic_firmware_available": false,
    "full_native_hardware_spec_available": false,
    "orao103_rom_substitution_valid": false,
    "acceptable_test_claim": "A successful Apple II+ program test validates only the experimental Apple-compatible profile and the exact features exercised.",
    "required_future_evidence": ["Verified reads of both original 16-KiB EPROMs", "PEL service/programming manual or traced schematic", "Address-decoder and I/O register mapping", "Native monochrome/color and local-character captures from a surviving machine"]
  }
}